METEOROLOGICAL CODES
Synoptic Code (SM,SN,SI)
Ship Synoptic Code (SM,SN,SI)
Drifting Buoy Data Code (SS)
Upper Air Code (Rawinsonde) (UA UF UG UH UI UV UK UL UM UP UQ US UX)
Satellite Derived Winds (TW)
Forecast Code (TAF) (FT)
Metar Code (SA,SP)
Radar Observation (FFAA) Code (SD, WO)
Australian Tropical Observations(WTAU)
Recco Code (URPA10 or 11)
Dropsonde Code (UZPA13)
Vortex Report Code (URPA12)
Vortex Data Code (URPA14)
Automatic Met Report from an Aircraft (UAV)
WC-130 Recon Decoder

SYNOPTIC CODE

98334  31475    82706   10252     20225      39858    40061  55008  60021   76062    83223
iii    iRixhVV  Nddff   1snTTT    2snTdTdTd  3pppp    4PPPP  5appp  6RRRtR  7wwW1W2  8NhCLCMCH 
sta             C/wind  Temp      DPT        StaPres  SLP    APP    Precip  Preswx   Clouds 

SHIP SYNOPTIC CODE

BBXX SHIP  24121  99122      71353       31475    82706  10252    20225      40061  55008
BBXX SHIP  YYGGIw 99LaLaLa   QcLoLoLoLo  iRixhVV  Nddff  1snTTT   2snTdTdTd  4PPPP  5appp
     ID    DTG    Lat        Long        Misc     Wind   Temp     DP         SLP    APP 

76062   83223     91312   22242   00234     20805     31215         40806         51005
7wwW1W2 8NhCLCMCH 9GGgg   222DsDv 0SsTwTwTw 2PwPwHwHw 3Dw1Dw1Dw2Dw2 4Pw1Pw1Hw1Hw1 5Pw2Pw2Hw2Hw2
Wea     Clouds    Ob Time Mvmnt   SST       Waves     Swl dir       Primary       Secondary

62052     80122     ICE 23223
6IsEsEsRs 8SwTbTbTb ICE ciSibiDizi
Ship ice  Wet Bulb  Ice Flows

DRIFTING BUOY DATA CODE

SMVD22 KWBC 011200 RRA
BBXX
MMMM
Type
46014   01121 99392    71240      46/// /0602 10125  40108 53004 91150  22200
IIiii   DDHHI 99LaLaLa QcLoLoLoLo II/// /ddff 1snTTT 4PPPP 5APPP 9HHmm  22200
Station Time  Lat      Long       Block Winds Temp   SLP   APP   Obtime 22200

00126     11703     70013    333 91203     555 11024 22025;
0snTsTsTs 1PwPwHwHw 70HwHwHw 333 9SpSpspsp 555 National Data
SST       Waves     Waves    333 special   555 National data

UPPER AIR CODE

Mandatory Levels

TTAA    52121  71853
Part A  DTG    Station

99001 09421 03003 00050  09421 03003 92750 21424 03011 85525 11056 25014 
SFC   T/DPD Wind  1000mb T/DPD Wind  925mb T/DPD Wind  850mb T/DPD Wind

70118 10062 11509 50585 03977 00508 40757 14970 31016 30967 32357 26518 25093 427// 
700mb T/DPD Wind  500mb T/DPD Wind  400mb T/DPD Wind  300mb T/DPD Wind  250mb T/DPD

26520 20241 511// 29523 15423 639// 26012 10666 701// 30010
Wind  200mb T/DPD Wind  150mb T/DPD Wind  100mb T/DPD Wind
 
88180 661// 33563 77176   33563 41008     51515 10164 00012
Trop  T/DPD Wind  Max Wnd Wind  Vec diff  regional additional data


Significant Levels

TTBB 52122 47991 Part B DTG Station 00010 27438 11898 18828 22893 20444 33575 00236 44545 01958 55533 03326 1st lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD 66493 06715 77422 12549 88398 16150 99391 17160 11386 17950 22380 18757 Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD Sig lvl T/DPD 31313 74702 81130 61616 11900 11521 22800 11021 33600 11027; 31313 SST and Sounding data 61616 Additional levels developed nationally Additional data is represented by the 21212, 31313, 41414, 51515-59595, and 61616-69696 groups.

Pilot Winds

PPBB 52126 47158 Pilot DTG Station 90012 32003 18005 16006 90346 11506 07506 08507 90789 10509 10510 10010 9k123 Wind1 Wind2 Wind3 9k456 Wind4 Wind5 Wind6 9k789 Wind7 Wind8 Wind9 91246 13005 22005 27004 9205/ 32509 30511 9305/ 23014 24524 950// 23016; 9k012 Wind10 Wind11 Wind12 9k34/* Wind13 Wind14 9k56/ Wind15 Wind16 9k7// Wind17 9 is the indicator for the winds at three significant levels (given in the following three groups) k indicates a 10,000 ft range (0 = 0-9000ft, 1=10,000-19,000ft, 2=20,000-29,000ft, etc) The next three numbers each represent the level for the Winds in thousands of feet (90012 = 9=Indicator, 0=Sfc-9000ft range, 0=Sfc wind hgt, 1=1000ft wind hgt, 2=2000ft wind hgt Wind1=Winds corresponding to the 3rd digit in the 9 group, Wind2- the 4th digit, Wind3- the 5th digit. A solidus (/) is entered when there are no more wind levels for that 1000ft range. This pattern repeats for all winds.
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SATELLITE DERIVED WINDS CODE


TWNA01 RJTD 031200
ICAO DTG

YYXX  53080  11461     152//    034///
YYXX  YYGGg  I1I2I2I3I4 I1I2I2//  I1I2I2//
Type  DTG    Satellite Information
 
333  11704    9727/       32024  9525/      31525  7322/       31038
333  B1B2B3nn  ULaULoPePe/  ddfff  ULaULoPePe/  ddfff  ULaULoPePe/  ddfff
Ind  Grid     Location    Winds  Location   Winds  Location    Winds

              3722/       36032
              ULaULoPePe/  ddfff
              Location    Winds

     20104    7919/       07016  3518/      04018  1120/       04516
     B1B2B3nn  ULaULoPePe/  ddfff  ULaULoPePe/  ddfff  ULaULoPePe/  ddfff
     Grid     Location    Winds  Location   Winds  Location    Winds


              1724/       05518
              ULaULoPePe/  ddfff
              Location    Winds

FORECAST CODE (TAF)


KFBG TAF  RTD 021111 18010KT 8000 BR SCT040 BKN250 QNH3010INS 620046 510003
ICAO Type Mod Valid  Wind    Vis  Wx Clouds Clouds Altimeter  Icing  Turbulence  

    BECMG  1314 22012G18KT 9999 VCTS SCT040 BKN250 QNH3008INS
    Change Time New winds  Vis  Wx   Clouds Clouds Altimeter

    TEMPO     1718 23015G25KT 4800 TSRA BKN015CB OVC050
    Temporary Time Tempo Wind Vis  Wx   Clouds   Clouds 

    BECMG  2223 22012G18KT 8000 SHRA BR BKN030CB OVC100 QNH3000INS
    Change Time New winds  Vis  Wx      Clouds   Clouds Altimeter

    T25/21Z   T18/11Z
    Max Temp  Min Temp
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METAR CODE

METAR           PGUA 181255Z  COR          12010G15KT          090V150  
METAR or SPECI  CCCC YYGGggZ  AUTO or COR  dddff(f)Gfmfm(fm)KT dndndnVdxdxdx 
Type of Report  Sta  DTG      Modifier     Wind                Variable wind

15SM      R03L/1600FT                                     VCSH   FEW018CB BKN120 BKN300
VVVVVSM  [RDRDR/VRVRVRVRFT or RDRDR/VNVNVNVNVVXVXVXVXFT]  w'w'  [NsNsNshshshs or VVhshshs or SKC/CLR]
Vis       RVR                                             Wx     Sky Condition

28/18        A2987       RMK  SLP096 CB 7 E MOV NW 
T'T'/T'dT'd  APHPHPHPH   RMK  (Automated, Manual, Plain Language) 
T/TD         Altimeter   Remarks

8/378 9/232 55007
(Additive Data and Automated Maintenance Indicators)
Additive Data

RADAR OBSERVATION CODE


SDAS KAWN 271800 RRX
FFAA      29030  47447    42364     11361      10314      30222;
MiMiMjMj   YYGGg  IIiii    4RwLaLaLa  QcLoLoLoLo  AcScWcacrt  tedsdsfsfs
Type      DTG    Station  Lat       Long       Char       Mvmnt 

AUSTRALIAN TROPICAL CYCLONE BOGUS


BTAB messages are coded summaries of tropical cyclone parameters. These messages are transmitted to Darwin RSMC in a specific computer-readable format. The data is then distributed by Darwin for use by international numerical weather prediction centres.



WTAU10 ADRM 271900
BTAB YPDM 02U BESSI 011127 1800 084S 0928E 240 035  0990 1008 0450 20  200 0200 0300 0300 0200 D ;
          Sid Stnam Dtg    HHmm Lat  Long  Dir Sm/s ChPa OhPa Rout Max Rad 30NE 30SE 30SW 30NW SD

RECCO CODE

URPA11 PGTW 161227
Standard Message Header
AF967 0212A LILI OB 08 PGTW
Mission data
97779  12314  40169     82508     04000    22020  25218    /0007     42115
9XXX9  GGggI  YQLaLaLa  LoLoLoBf  hhhdtda  ddfff  TTTdTdw  /jHHH     4ddff 
Group  Time   Lat       Long      Altit    Winds  T/Td     Sfc Pres  Sfc Wind

14132     92080  62040  46262  11500     28080  60081      77186      75760   80366      81732
1kNsNsNs  ChhHH  ChhHH  ChhHH  1kNsNsNs  ChhHH  6WsSsWddw  7IrItSbSe  7hhHH   8drdrSrOe  8EwElceie
Clouds    Hgts   Hgts   Hgts   Clouds    Hgts   Sig Wx     Icing loc  Icg Hgt Radar      Echo

DROPSONDE CODE

UZPA13 PGTW 061851
XXAA 56185  99251   70786     08158    99016   26444     18501     00140     26247    07004
XXAA YYGGId 99LaLaLa QcLoLoLoLo MMMUlaUlo 99PoPoPo ToToToDoDo dodofofofo P1P1h1h1h1 T1T1T1D1D1 d1d1f1f1f1
ID   DTG    Lat     Long      Marsden  Surface Data                Standard Isobaric Surface

88100   52160     /////     77200   09045     41210
88PnPnPn TnTnTnDnDn dndnfnfnfn 77PnPnPn dndnfnfnfn 4vbvbvava
Tropopause Data             Max Wind Data

61616 AF968 0204A BONNIE OB 04
61616 AFXXX XXXXX XXXXX OB X KXXX
Mission Information

62626 RAINBAND SPL 2635N08996W LST WND 001 MBL WND 04010
62626
Nationally Developed Codes

XXBB 56188 99251   70786     08158    00016   26444     11005     25841   
XXBB YYGG8 99LaLaLa QcLoLoLoLo MMMUlaUlo 00PoPoPo ToToToDoDo nonoPoPoPo ToToToDoDo  
ID   DTG   Lat     Long      Marden   SLP     SL Temp   Sig Lvl   T/DPD 

31313 09608     81828
31313 srrarasasa 8GGgg
Sounding Information

51515 10166 02050
51515 101XX 0PnPnPnPn
Additional Data Groups

61616 AF968 0204A BONNIE OB 04
61616 AFXXX XXXXX XXXXX OB X KXXX
Mission Information

62626 RAINBAND SPL 2635N08996W LST WND 001 MBL WND 04010
62626
Nationally Developed Codes

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VORTEX REPORT CODE


URPA12 PGTW 051237
VORTEX DATA MESSAGE
A. 05/1237Z
B. 30 DEG 59 MIN N
77 DEG 16 MIN W
C. 700 MB 2695 M
D. 65 KT
E. 050 DEG 80 NM
F. 313 DEG 78 KT
G. 063 DEG 32 NM
H. 954 MB
I. 11 C/ 3082 M
J. 15 C/ 3108 M
K. 13 C/ NA
L. CLOSED WALL
M. C25
N. 12345/7
O. 1/1 NM
P. AF984 1606A FRAN OB 14
MAX FL WIND 105 KT NE QUAD 1051Z. STADIUM EFFECT.
MAX FL TEMP 17C 130/10 NM FROM FL CENTER.


VORTEX DATA CODE


URPA14 PGTW 020031
AF985 1605A EDOUARD OB 16 PGTW
SUPPLEMENTARY VORTEX DATA MESSAGE
Header

01401    10721     13086 10303   04044
01LaLaLa 1LoLoLoLo 1jHHH 1TTTdTd ddfff

02400    20719     23068 20505   06048
02LaLaLa 2LoLoLoLo 2jHHH 2TTTdTd ddfff

03398    30716     33052 30606   07045
03LaLaLa 3LoLoLoLo 3jHHH 3TTTdTd ddfff

04396    40714     43038 40606   06036
04LaLaLa 4LoLoLoLo 4jHHH 4TTTdTd ddfff

05394    50711     53020 50706   06048
05LaLaLa 5LoLoLoLo 5jHHH 5TTTdTd ddfff

06391    60709     63986 60707   05050
06LaLaLa 6LoLoLoLo 6jHHH 6TTTdTd ddfff

07388    70706     73949 70907   04051
07LaLaLa 7LoLoLoLo 7jHHH 7TTTdTd ddfff

08386    80704     83914 80908   04048
08LaLaLa 8LoLoLoLo 8jHHH 8TTTdTd ddfff

09385    90702     93872 91010   04047
09LaLaLa 9LoLoLoLo 9jHHH 9TTTdTd ddfff

10384    00699     03813 01311   04041
10LaLaLa 0LoLoLoLo 0jHHH 0TTTdTd ddfff

MF398    M0717     MF058
MFLaLaLa MLoLoLoLo MFfff

OBS 01 AT 2122Z
OBS 01 AT HHMMZ

OBS XX AT HHMMZ
OBS 10 AT 2205Z

OBS 06 SFC WND /////
OBS 01 SFC WND ddfff

REMARKS;

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Automatic Met Report from an Aircraft


AMDAR YYGG
MANOP Time

ipipip  IA...IA  LaLaLaLaA  LoLoLoLoLoB  GGgg  ShhIhIhI  SSTATATA  {SSTdTdTd or UUU}  ddd/fff   TBBA
Phase  ACFT ID  Lat       Long       Time   PA       Temp      DP or RH          Wind     Turb

SS1S2S3  333  Fhdhdhd    VGfgfgfg
System  Ind  PA(ACARS)  Vert Gust(ACARS)

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           CODE BREAKDOWNS

SYNOP CODE


iii iRixhVV Nddff 1snTTT 2snTdTdTd 3pppp 4PPPP 5appp 6RRRtR 7wwW1W2 8NhCLCMCH 
333 1snTxTxTx 2snTnTnTn 3EsnTgTg 4E'sss 8NsChshs 9SpSpspsp
555 1V'f'/V'f''f' 2snTwTwTw

SECTION 0
	iii iRixhVV

SECTION 1
	Nddff 1snTTT 2snTdTdTd 3pppp 4PPPP 5appp 6RRRtR 7wwW1W2 8NhCLCMCH

SECTION 3
333	1snTxTxTx (at 1800 UTC) 2snTnTnTn (at 0600 UTC)	3EsnTgTg (at 0600 UTC)	
	4E'sss (at 0600 UTC) 8NsChshs 9SpSpspsp

SECTION 5
555	1V'f'/V'f''f'' 2snTwTwTw

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Interpretation

SECTION 0
iii         Station Number

iRixhVV     iR      Inclusion or omission of precipitation data
            ix      Inclusion or omission of weather group
            h       Height of base of lowest cloud
            VV      Horizontal visibility

SECTION 1
Nddff       N       Total Cloud amount
            dd      Wind direction in tens of degrees
            ff      Wind speed in knots

1snTTT      1       Indicator
            sn      Sign of temperature
            TTT     Dry-bulb temperature to the tenth of a degree Celsius
            (10302 = +30.2C)

2snTdTdTd   2       Indicator
            sn      Sign of temperature
            TdTdTd  Dew-point temperature to the tenth of a degree Celsius
            (20281 = +28.1C)

3pppp       3       Indicator
            pppp    Station level pressure.  Rarely used now. Not used in a station plot. 

4PPPP       4       Indicator
            PPPP    Last four figs. of air pressure (reduced to mean sea level) in millibars
 and tenths (49882 = 988.2 mb)

5appp       5       Indicator
            a       Characteristic of pressure change
            ppp     Pressure change over last three hours in millibars and tenths

6RRRtR      6       Indicator
            RRR     Amount of rainfall
            tR      Duration of period of RRR in units of six hours.  Main hours only
                    At 0001 and 1200 UTC tR=1   At 0600 and 1800 tR=2

7wwW1W2     7       Indicator
            ww      Present weather, manned station
            W1W2    Past weather, manned station

8NhCLCMCH   8       Indicator
            Nh      Amount of low cloud, or medium cloud if no low cloud present
            CL      Form of low cloud
            CM      Form of medium cloud
            CH      Form of high cloud

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SECTION 3

333         Regional Indicator
1snTxTxTx   1       Indicator
            sn      Sign of temperature
            TxTxTx  Maximum temperature 0600-1800 UTC in tenths of a degree

2snTnTnTn   2       Indicator
            sn      Sign of temperature
            TnTnTn  Minimum temperature 1800-0600 UTC in tenths of a degree

3EsnTgTg    3       Indicator
            E       State of ground without snow or measurable ice cover
            sn      Sign of temperature
            TgTg    Grass minimum temperature rounded to nearest whole degree

4E'sss      4       Indicator
            E'      State of ground with snow or measurable ice cover
            sss     Depth of snow

8NsChshs    8       Indicator
            Ns      Amount of individual cloud layer
            C       Form of cloud
            hshs    Height of base of cloud layer

Up to four layers of significant cloud can be reported (using 8NhChshs groups).
The rules for the selection of significant cloud layers are:

	1.   The lowest layer of any amount
	2.   The next lowest layer of 3 oktas (eighths) or more.
	3.   The next lowest layer of 5 oktas or more.
	4.   Any cumulonimbus cloud not already reported under 1, 2 or 3 above,
             regardless of amount.

Clouds are reported in order of ascending height.
Cumulonimbus cloud reported under rule 4 above would be inserted between the
other groups at its correct height level - regardless of the amount of
Cumulonimbus being reported.

9SpSpspsp       9       Indicator
                        This group is included when necessary to report special phenomena.

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SECTION 5
555		National indicator (This section is not sent when there are no data to report)
1V'f'/V'f''f''	1	Indicator
		V'V'	Visibility in meters (reported when visibility is less than 100 m)
		(f')f'f'	Speed in knots of the maximum gust in the past hour (>33 kts)

2snTwTwTw	2	Indicator
		sn	Sign of temperature
            	TwTwTw  Sea temperature in tenths of a degree

CODE TABLES

Table 1:iR  Indicator for inclusion or omission of precipitation data

Code
Figure	Precipitation data are reported:	Group 6RRRtR is:
1	in Section 1	                        included
2	in Section 3	                        included
3	in none of the two Sections 1 and 3	omitted (precipitation amount =0)
4	in none of the two Sections 1 and 3	omitted (precipitation amount not available)

Note:  UK practice only, code figures 1,3 and 4 to be used


Table 2:ix  Indicator for type of station operation (manned or automatic)
            and for present and past weather
Code
figure	Type of station operation   Group 7wwW1W2 or 7wawaWa1Wa2 is:
1	manned	                    included
2	manned	                    omitted (no significant phenomena to report)
3	manned	                    omitted (not observed, data not available

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SHIP SYNOP CODE

Section 0 BBXX DDDD YYGGi w 99LaLaLa QcLoLoLoLo.
DDDD.  This is the four letter ship international radio call sign (IRCS).  This group
 is entered on the observation form and is transmitted in the observation.  This is
 the only group with only four elements in the code.
YYGGiw.  This group identifies the date and time of the observation, and information
 about the wind group.
 a.  YY - The day of the month (UTC) in two digits, i.e., the second is entered as 02,
 the thirteenth as 13, etc.  Note that the date UTC will vary by a day from the date
 LST on certain hours of the day, depending on the time zone.
 b.  GG - The hour of observation (UTC) in two digits, i.e., 0900 UTC is entered as 09,
 1200 UTC as 12, etc.  Observation times are at three hour intervals starting at 0000
 UTC, i.e., 00, 03, 06, etc.   
 c.  iw - Navy ships will report wind speed in knots.  The code figure indicating how
 the wind speed was observed and encode is as follows:
  (1) If wind speed is estimated: Code figure 3.
  (2) If wind speed is measured:  Code figure 4.
99LaLaLa.  This group identifies the latitude of
 the ship at the time of observation.
 a.  99 - Indicates that latitude information follows.
 b.  LaLaLa - The latitude to the tenth of a degree.  To obtain the tenths value, divide
 the minutes of latitude by 6 and disregard the remainder.
QcLoLoLoLo.  The group identifies the quadrant of the globe that the ship is in and the
 longitude of the ship at the time of observation.
 a.  Qc - The code figure that indicates the quadrant of the globe the ship is in.
 b.  LoLoLoLo - The longitude to the tenth of a degree. 
To obtain the tenths value divide the minutes of longitude by 6 and disregard the remainder.

Qc - Quadrant of the Globe
                               N
                               |
                         Q = 7 |  Q = 1
                   W --------- |---------- E Equator
                         Q = 5 |  Q  = 3
                               |
                               S
 
                 Code
                Figure    Latitude   Longitude
                   1       North      East
                   3       South      East
                   5       South      West
                   7       North      West
NOTE:  The choice is left to the observer in the following cases:
When the ship is on the Greenwich meridian or the 180th meridian
(LoLoLoLo = 0000 or 1800 respectively):
Qc = 1 or 7 (northern hemisphere) or
Qc = 3 or 5 (southern hemisphere)
When the ship is on the Equator (LaLaLa = 000):
Qc = 1 or 3 (eastern longitude) or 
Qc = 5 or 7 (western longitude)

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9GGgg.  This group identifies if the actual time of the observation is not within 10 minutes
 of the standard reporting time.  Since most observation reports are made within ten minutes
 of the standard time, this group will usually not be included.
 a.  9 - Indicator.
 b.  GG - Time in whole hours UTC.
 c.  gg - Time in whole minutes UTC.
222Dsvs.  This group identifies the direction and speed of the ship.
 a.  222 - Identifies the beginning of section 2 of the code.
 b.  Ds - The code figure representing the direction of the movement of the ship during the
 three hours preceding the time of observation.
 c.  vs - The code figure indicating the average speed made good during the three hours
 preceding the time of observation.
OssTwTwTw.  This group indicates the sea water temperature in degrees Celsius.
 a.  O - Identifies the sea water temperature group in section 2 of the code.  If the
 temperature cannot be observed, the entire group is deleted from the observation and group
 O will not appear in section 2.
 b.  ss - The code figure indicating the sign and type of sea water temperature.
 c.  TwTwTw - The sea water temperature in tens, units, and tenths degrees Celsius.  
2PwPwHwHw.  This group indicates the  wind wave data determined from visual observation.
 a.  2 - Identifies the wind wave group in section 2 of the code.
 b.  PwPw - The average period of the significant wind waves in seconds.  A period of three
 seconds is entered as 03, a period of twelve seconds as 12.  Calm is entered as 00, 99 if
 period is confused.
 c. HwHw - The code figure indicating the height of the wind waves.
3dw1dw1dw2dw2.  This group indicates the directions of the primary and secondary swell waves.
 a.  3 - Identifies the swell wave direction group in section 2 of the code.  If element is
 not observed it is encoded as 30000.
 b.  dw1dw1 - Hundreds and tens of degrees of the direction from which the primary swell is
 coming from.
 c.  dw2dw2 - Hundreds and tens of degrees of the direction from which the secondary swell is
 coming from.
 If there is only one swell present, "00" is entered for dw2dw2.
4Pw1Pw1Hw1Hw1.  This group indicates the primary swell wave data.
 a.  4 - Identifies the primary swell wave group in section 2 of the code when no swell is
 present.  If the element is not observed, 40000 is encoded.
 b.  Pw1Pw1 - The average period of the primary swell waves in seconds.  A period of three
 seconds is 03, a period of twelve seconds is 12, etc..
 c.  Hw1Hw1 - The code figure indicating the height of the primary swell waves.
5Pw2Pw2Hw2Hw2.  This group indicates the secondary swell wave group in section 2 of the code.
 If the element is not observed, it is encoded as 50000.
 a.  Pw2Pw2 - The average period of the primary swell waves in seconds.  A period of three
 seconds is 03, a period of twelve seconds is 12, etc.
 b.  Hw2Hw2 - The code figure indicating the height of the primary swell waves.
6IsEsEsRs.  This group identifies the state of ice accretion on the ship at the time of
 observation.  The entire group is omitted from the report if ice is not observed.
 a.  6 - Identifies the ice accretion group in section 2 of the code.
 b.  Is - The code figure identifying the source of the ice accretion.
 c.  EsEs - The average thickness of the ice in centimeters. 
 d.  Rs - The code figure identifying the rate of buildup of the ice accretion.
8SwTbTbTb.This group identifies the wet-bulb temperature in degrees Celsius.
 a. 8 - Identifies the wet bulb temperature group in section 2 of the code.
 b.  Sw- The sign and type of wet-bulb temperature.
 c.  TbTbTb - The wet-bulb temperature in tens, units, and tenths degree Celsius.  
ICE + Plain Language or ICE ciSibiDizi.  This group identifies the presence and state of sea ice
 and ice of land origin.
 a.  ICE - Indicates that the sea ice group is present in section 2 of the code.  When no sea
 ice or ice of land origin is observed, this group will be omitted from the code.
 b.  ci - The code figure that best describes the concentration and arrangement of the sea ice
 at the time of observation.
 c.  Si - The code figure that best describes the stage of development of the sea ice at the
 time of observation.
 d.  bi - The code figure that best describes the ice of land origin present at the time of
 observation.
 e.  Di - The code figure that best describes the orientation of the principle edge of the sea
 ice at the time of observation.
 f.  zi - The code figure that best describes the effect of the sea ice on the ship over the
 past three hours.
 g.  Plain Language - Remarks considered significant by the observer.

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UPPER AIR CODE

MMMM.  Bulletin type for data.

IIiii.  WMO block and buoy identifier.

DDHHI.  Date Time Group.
 a.  DD.  Day of the month in two digits.
 b.  HH.  Zulu hour for the observation.
 c.  I.   Indicator for the source of wind speed.  1 or 2 = knots, 3 or 4 = meters per second.

99LaLaLa.  Latitude.  Standard group for latitude
 a.  99.  Indicator for the group.
 b.  LaLaLa.  Latitude reported to the nearest tenth of a degree.

QcLoLoLoLo.  Longitude.  Standard group for longitude.
 a.  Qc.  Quadrant of the globe.
    1 = N and E
    3 = S and E
    5 = S and W
    7 = N and W
 b.  LoLoLoLo.  Longitude to the nearest tenth of a degree.

II///.  WMO Block.

/ddff.  Winds.
 a.  dd.  Wind direction to the nearest ten degrees in two digits (hundreds and tens digits)
 b.  ff.  Wind speed.

1SnTTT.  Temperature.
 a.  1.  Indicator for the group.
 b.  Sn.  Sign of the temperature.  0 = positive, 1 = negative.
 c.  TTT. Temperature to the nearest tenth of a degree Celsius.

4PPPP.  Air pressure at mean sea level.

5APPP.  Pressure tendency group
 a.  5.  Indicator for the group.
 b.  A.  Coded tendency number
 c.  PPP.  Pressure change.

9HHMM.  Actual time the observation was taken.
 a.  9.  Indicator for the group.
 b.  HH.  Hour of the observation.
 c.  MM.  Minute of the observation.

22200.  Indicator for observed maritime conditions.

0snTsTsTs.  Sea Surface Temperature group.
 a.  0.  Indicator for the group.
 b.  sn.  Sign of the SST.
 c.  TsTsTs.  Sea Surface Temperature in tenths of a degree Celsius.

1PwPwHwHw.  Wave period and height.
 a.  1.  Indicator for the group.
 b.  PwPw.  Wave period.
 c.  HwHw.  Wave height to the nearest 10 meters.

70HwHwHw.  Additional Wave data.
 a.  70.  Indicator for the group.
 b.  HwHwHw.  Wave height to the nearest meter.

333.  Indicator for regionally assigned data.

9SpSpSpSp.  Special data.

555.  Nationally assigned data.
 
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UPPER AIR CODE


TTAA 52121 71853 99001    09421       03003      00050  09421  03003 85525 11056  25014
TTAA YYGGI IIiii 99PoPoPo ToToTaoDoDo dododofofo 00hhh  TTTaDD dddff 85hhh TTTaDD dddff

88180    661//       33563      77176    33563      41008     51515 10164 00012
88PtPtPt TtTtTatDtDt dtdtdtftft 77PmPmPm dmdmdmfmfm vbvb0vava 51515 101AdfAdf

TTAA. Identifies Part A of the Temp Ship code. 
YYGGI Date Time Group.
 a. YY.  Identifies the date in two digits.
 b. GG.  Identifies the zulu hour in two digits.
 c. I.   Indicates the highest mandatory level for which winds are reported.
IIiii.  The station block and number.
99popopo Indicator for surface data.
 a.  99.  Indicator.
 b.  popopo.  The code for the surface pressure.
TtTtTatDtDt Temperature and Dew Point Depression at the surface.
 a.  TtTt.  Surface temperature in degrees Celsius.
 b.  Tat.   Sign for the surface temperature.  0=positive temps, 1=negative temps.
 c.  DtDt.  Dew Point Depression for the Surface.  Subtract this from the temperature to get
 surface Dew Point.
dtdtdtftft  Surface winds.
 a.  dtdtdt.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is
 added to the direction.
  (ex: 112 degrees at 112 kts = 11112, 110 degrees plus 1. 115 degrees at 112 kts = 11612, 115
 degrees plus 1)
 b.  ftft.  Wind speed in whole knots.
00hhh 1000mb level pressure height.
 a.  00.  Indicator for 1000mb data.
 b.  hhh. Coded pressure height.
TTTaDD Temperature and dew point for the pressure level
 a.  TT.  Pressure level temperature in degrees Celsius.
 b.  Ta.  Sign for the temperature.  0=positive temps, 1=negative temps.
 c.  DD.  Dew Point Depression for the pressure level.  Subtract this from the temperature to
 get the Dew Point.
dddff Wind at the pressure level.
 a.  ddd.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is added
 to the direction.
 b.  ff.  Wind speed in whole knots.
85hhh 850mb level pressure height.
 a.  85.  Indicator for the 850 mb height.
 b.  hhh.  Coded pressure height.
TTTaDD Temperature and dew point for the pressure level
 a.  TT.  Pressure level temperature in degrees Celsius.
 b.  Ta.  Sign for the temperature.  0=positive temps, 1=negative temps.
 c.  DD.  Dew Point Depression for the pressure level.  Subtract this from the temperature to
 get the Dew Point.
dddff Wind at the pressure level.
 a.  ddd.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is added
 to the direction.
 b.  ff.  Wind speed in whole knots.
88PtPtPt  Tropopause data.
 a.  88.  Indicator for tropopause data.
 b.  PtPtPt.  Pressure height of the tropopause.
TtTtTatDtDt Temperature and dew point for the pressure level
 a.  TtTt.  Tropopause temperature in degrees Celsius.
 b.  Tat.   Sign for the tropopause temperature.  0=positive temps, 1=negative temps.
 c.  DtDt.  Dew Point Depression for the tropopause.  Subtract this from the temperature to get
 trop Dew Point.
dtdtdtftft  Winds at the Tropopause.
 a.  dtdtdt.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is
 added to the direction.
 b.  ftft.   Wind speed in whole knots.
77PmPmPm Max wind pressure level. (if this is at or above the data field group starts with 66)
 a.  77.  Indicator for the Max Wind data.
 b.  PmPmPm.  Coded pressure at the Maximum Wind Level.
dmdmdmfmfm Maximum winds
 a.  dmdmdm.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is
 added to the direction.
 b.  fmfm.   Wind speed in whole knots. 
VbVb0VaVa Vector difference above and below the max wind level.
 a.  VbVb.  Vector difference between the Max wind level and the winds 3000 feet below.
 b.  VaVa.  Vector difference between the Max wind level and the winds 3000 feet above.
21212 -Data for additional levels, with respect to winds.
31313 -Data for Sea Surface Temperature and Sounding System.
41414 -Wind data.
51515 101AdfAdf.  Coded data assigned regionally.
51515-59595 -Code groups developed regionally.
61616-69696 -Code groups developed nationally.

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PART B

TTBB 5212/  71853
TTBB YYGG/  IIiii

00975 09421  11921 14457
00ppp TTTaDD 11ppp TTTaDD

PPBB 52120 72764
PPBB YYGGa IIiii

90023     12507  14511 18518
9tnu1u2u3 dddff  dddff dddff

TTBB.  Indicator for Part B of the Temp Ship bulletin.
YYGG/.  Date and hour of the observation.
IIiiii.  Station block and number.
00ppp.  First significant level. Each additional level is numbered accordingly.
 a.  00.  Indicator for group.
 b.  ppp.  Pressure height for the group.
TTTaDD.  Temperature and dew point for the pressure level
 a.  TT.  Pressure level temperature in degrees Celsius.
 b.  Ta.  Sign for the temperature.  0=positive temps, 1=negative temps.
 c.  DD.  Dew Point Depression for the pressure level.  Subtract this from the temperature to
 get the Dew Point. 
PPBB.  Indicator for the Pilot Ship winds report.
YYGGa.  Date Time Group.
 a. YY.  Identifies the date in two digits.
 b. GG.  Identifies the zulu hour in two digits.
 c. a.   Indicator specifying type of wind measuring equipment used (0- pressure and wind
 instruments; 1,2- theodolite; 3- radar; 4- same as 0, but the equipment failed during the
 ascent.)
9tnu1u2u3.  Identifies the heights of the following three wind groups.
 a.  9.  Indicator for this group.
 b.  tn  Tens digit of the altitude, expressed in increments of 10,000' MSL applying to the
 data groups which follow. Example: "4" means winds between 40.000' and 50,000' MSL follow.
 c.  u1,u2,u3  Units digit of the altitude, expressed in increments of 1,000 feet, which applies
 to the first, second, and third data groups following.
dddff.  Wind at the identified level.
 a.  ddd.  Wind direction to the nearest 5 degrees. For wind speeds over 100 knots, 1 is added
 to the direction.
 b.  ff.  Wind speed in whole knots.
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SATELLITE DERIVED WINDS CODE

ICAO  Reporting Station.
DTG  Date Time Group of Bulletin.
YYXX  Bulletin Type.
YYGGg  Valid time of report. 
  a.  YY.  Day of the month.  If 50 is added to the date, winds are reported in knots.
      If not winds are in Meters per second.
  b.  GG.  Valid hour (08=0800 Zulu).
  c.  g.   Valid time in tens of minutes.
I1I2I2I3I4 I1I2I2//  I1I2I2//  Coded information pertaining to the satellite used.
333  Indicator for wind data at specified pressure levels.
B1B2B3nn  Grid and number of reports for the grid.
  a.  B1  Quadrant of the globe.
          Code                                  Code
         Figure   Longitude   Hemisphere       Figure    Longitude    Hemisphere
            0     0o- 90oW     Northern           5       0o- 90oW     Southern
            1    90o-180oW     Northern           6      90o-180oW     Southern
            2   180o- 90oE     Northern           7     180o- 90oE     Southern
            3    90o-  0oE     Northern           8      90o-  0oE     Southern
  b.  B2.  Tens digit for the latitude (3 = 30 degrees).
  c.  B3.  Tens digit for the longitude (3 = 30 or 130 degrees depending on the quadrant of the globe).
  d.  nn.  Number of consecutive isobaric surface wind reports for this grid square.   
ULaULoPePe/  Location within the grid and Pressure level. 
  a.  ULa.  Latitude digit.  Equals one degree latitude within the 10o X 10o grid square.
  b.  ULo.  Longitude digit.  Equals one degree longitude within the 10o X 10o grid square.
  c.  PePe.  Estimated pressure in tens of hectopascals where cloud displacement was observed.
dddff Winds.
  a.  ddd.  Wind direction to the nearest 5 degrees (third digit being a 0 or a 5 unless speed exceeds 100).
  b.  ff.   Wind speed to the nearest whole number (knots or meters per second).  For speeds exceeding 100, a 1 is added to the 
      digits (third number of the wind group) of the direction.  This makes the ones digit of the wind direction either a 1 or a 5.
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FORECAST CODE

ICAO  
    Location identifier.  This four letter identifier states the location that
    the forecast  is valid for. i.e BECMG states that there's a gradual change in the
    weather between 1300Z and 1400Z.

Type  
    Message Type- TAF(Terminal Airdrome Forecast).
  
Mod  
    Modifier (AMD, COR, AMD COR, RTD). 
    a. AMD - Forecast was amended. 
    b. COR - Forecast was corrected. 
    c. AMD COR - Forecast was initially amended then corrected.
    d. RTD - Forecast was transmitted late.
  
Valid
    Valid Period.  The valid period consists of the current date and the 24 hr.
    period of the forecast.
  
Wind
    Surface Wind Direction, Speed, and Gust if any. 
     a. ddd. Forecast true wind direction (from which wind is blowing) to the nearest 10 degrees. 
     b. ff. Mean forecast wind speed in whole knots (KT) which is the unit indicator for speed.
     c. Ggg.  Maximum wind speed in whole knots (KT).

Vis
    Forecast prevailing visibility in meters. Whenever
    visibility is forecast to be 9000 or less, the weather phenomena, obscuration to
    visibility, or vicinity remark will be included.

Visibility Conversion
        Statute              Statute              Statute
Meters  Miles        Meters  Miles        Meters  Miles  
------  -------      ------  -------      ------  -------
  0000  0              1200  3/4            3000  1 7/8  
  0100  1/16           1400  7/8            3200  2      
  0200  1/8            1600  1              3600  2 1/4  
  0300  3/16           1800  1 1/8          4000  2 1/2  
  0400  1/4            2000  1 1/4          4400  2 3/4  
  0500  5/16           2200  1 3/8          4800  3      
  0600  3/8            2400  1 1/2          6000  4      
  0800  1/2            2600  1 5/8          8000  5      
  1000  5/8            2800  1 3/4          9000  6      
                                            9999  7+     

INTENSITY DESCRIPTOR PRECIPITATION OBSCURATION OTHER
-  Light MI Shallow DZ Drizzle BR Mist PO Dust/Sand Whirls
   Moderate PR Partial RA Rain FG Fog SQ Squalls
+  Heavy BC Patches SN Snow FU Smoke FC Funnel Cloud/Tornado
  DR Drifting SG Snow Grains VA Volcanic Ash SS Sandstorm
VC Vicinity BL Blowing IC Ice Crystals DU Dust DS Duststorm
  SH Showers IP Ice Pellets SA Sand  
TS Thunderstorm GR Hail HZ Haze NSW No Significant Weather
FZ Freezing GS Small Hail or Snow Pellets PY Spray  
 
Wx
    Forecast weather phenomena, obstruction to visibility, or
    vicinity remark which will cause visibility to decrease or weather that is expected
    within 5 to 10 miles (vicinity e.g. VCTS).
  
Clouds
    Cloud layer group. This group has two sections: 
    Cloud amount:  SKC (no clouds), FEW (TRACE to 2 oktas),
    SCT (3 to 4 oktas), BKN (5 to 7 oktas), and OVC (8 oktas). 
    Cloud heights:  Forecast height (AGL) of cloud base to
    nearest 100 feet from surface (040; ten thousands, thousands, and hundreds of feet).
  
Altimeter
    Minimum altimeter setting. (30.10 inches)
  
Icing
    Icing Group.
    6. Icing Indicator.
    2. Type of Icing forecast.
    004. Height of the icing layer base in hundreds of feet AGL.
    6. Thickness of the icing layer in thousands of feet AGL.
AFW Icing "6 Group"
Code Figure Type of Icing

0

No Icing

1

Light Icing (mixed)

2

Light Icing in cloud (RIME)

3

Light Icing in precipitation (clear)

4

Moderate Icing (mixed)

5

Moderate Icing in cloud (Rime)

6

Moderate Icing in precipitation (clear)

7

Severe Icing (mixed)

8

Severe Icing in cloud (Rime)

9

Severe Icing in precipitation (clear)
Turbulence
    Turbulence Group. 
    5. Turbulence Indicator.
    1. Turbulence type and intensity.
    000. Height of the turbulence layer base in hundreds of feet AGL.
    3. Thickness of the turbulence layer in thousands of feet AGL.
AFW Turbulence "5 Group"
Code Figure

Turbulence Type & Intensity

0

None

1

Light Turbulence

2

Moderate clear air Turbulence, occasional

3

Moderate clear air Turbulence, frequent

4

Moderate in cloud Turbulence, occasional

5

Moderate in cloud Turbulence, frequent

6

Severe clear air Turbulence, occasional

7

Severe clear air Turbulence, frequent

8

Severe in cloud Turbulence, occasional

9

Severe in cloud Turbulence, frequent

X

Extreme Turbulence

Occasional

Occuring less than 1/3 of the time
  
Change
    Change group.
    Indicates that the predominant conditions will be changing during the given time period.

Change Time
    The time period for which the forecasted conditions will change.
    The first two numbers indicate the start of the change period and the last two numbers
    indicate the time the change should be completed. (BECMG 1314 = conditions will change
    between 13 and 14Z to...)

Temporary
    Temporary conditions.
    Indicates that the following conditions will be experienced temporarily during the
    given time period.

Tempo Time
    Time period of the temporary conditions.
    The first two numbers indicate the earliest the conditions could take place, the last two 
    numbers indicate the latest the conditions could take place. (TEMPO 1318= The following 
    conditions may temporarily occur between 13Z and 18Z)

Max/Min Temp
    The Forecast Surface Temperature Group. 
    T - an indicator, meaning temperature
    25 - the forecast max/min temperature in whole degrees Celsius (C)
    21Z - the valid time to the nearest whole hour UTC of the temperature forecast
    and Z is an abbreviated symbol meaning Universal Coordinated Time (UTC)
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METAR CODE

Type of Report (METAR and SPECI). The type, METAR or SPECI, shall be included in all reports. The type of report shall be separated from elements following it by a space. Whenever SPECI criteria are met at the time of the routine METAR, the type of report shall be METAR.

Station Identifier (CCCC). The station identifier, CCCC, shall be included in all reports to identify the station to which the coded report applies. The station identifier shall consist of four alphabetic-only characters if the METAR/SPECI is transmitted long-line. The agency with operational control when the station is first established shall be responsible for coordinating the location identifier with the FAA. A list of approved identifiers can be found in the FAA Manual 7350 Series, Location Identifiers.

Date and Time of Report (YYGGggZ). The date, YY, and time, GGgg, shall be included in all reports. The time shall be the actual time of the report or when the criteria for a SPECI is met or noted (see paragraph 2.6.4). If the report is a correction to a previously disseminated report, the time of the corrected report shall be the same time used in the report being corrected. The date and time group always ends with a Z indicating Zulu time (or UTC). For example, METAR KDCA 210855Z would be the 0900 scheduled report from station KDCA taken at 0855 UTC on the 21st of the month.

Report Modifier (AUTO or COR). The report modifier, AUTO, identifies the METAR/SPECI as a fully automated report with no human intervention or oversight. In the event of a corrected METAR or SPECI, the report modifier, COR, shall be substituted in place of AUTO.

Wind Group (dddff(f)Gfmfm(fm)KT_dndndnVdxdxdx). The standards for observing and reporting wind are described in Chapter 5.

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The wind direction, ddd, shall be coded in tens of degrees using three figures. Directions less than 100 degrees shall be preceded with a "0". For example, a wind direction of 90 is coded as "090". The wind speed, ff(f), shall be coded in two or three digits immediately following the wind direction. The wind speed shall be coded, in whole knots, using the units and tens digits and, if required, the hundreds digit. Speeds of less than 10 knots shall be coded using a leading zero. The wind group shall always end with KT to indicate that wind speeds are reported in knots. For example, a wind speed of 8 knots shall be coded "08KT"; a wind speed of 112 knots shall be coded "112KT".

  a. Gust.  Wind gusts shall be coded in the format,
     Gfmfm(fm) (see paragraphs 5.4.4 and 5.5.4). The wind
     gust shall be coded in two or three digits immediately
     following the wind speed. The wind gust shall be coded, in
     whole knots, using the units and tens digits and, if required,
     the hundreds digit.  For example, a wind from due west at
     20 knots with gusts to 35 knots would be coded "27020G35KT".

  b. Variable Wind Direction (Speeds 6 knots or less). Variable
     wind direction with wind speed 6 knots or less may be coded as
     VRB in place of the ddd (see paragraphs 5.4.2 and
     5.5.3).  For example, if the wind is variable at three knots,
     it would be coded "VRB03KT".

  c. Variable Wind Direction (Speeds greater than 6 knots).
     Variable wind direction with wind speed greater than 6 knots
     shall be coded in the format, dndndnVdxdxdx.  The variable
     wind direction group shall immediately follow the wind group
     (see paragraphs 5.4.2 and 5.5.3).  The directional variability
     shall be coded in a clockwise direction.  For example, if
     the wind is variable from 180 to 240 at 10 knots, it would be
     coded "21010KT 180V240".

  d. Calm Wind.  Calm wind shall be coded as "00000KT"
     (see paragraph 5.5.2).
Visibility Group (VVVVVSM). The standards for observing and reporting visibility are described in Chapter 6.

The surface visibility, VVVVVSM, shall be coded in statute miles using the values listed in Table 12- 1. A space shall be coded between whole numbers and fractions of reportable visibility values. The visibility group shall always end with SM to indicate that the visibility is in statute miles. For example, a visibility of one and a half statute miles would be coded "1 1/2SM".

Automated stations shall use an M to indicate "less than" when reporting visibility. For example, "M1/4SM" means a visibility of less than one-quarter statute mile.

Table 12-1. Reportable Visibility Values
Source of Visibility Report
AutomatedManual
2 0 5/8 1 5/8 4 12
¼ 10 1/16 ¾ 5 13
½ 3 1/8 7/8 1 7/8 6 14
¾ 4 3/16 1 2 7 15
1 5 ¼ 1 1/8 8 20
5/16 9 25
7 3/8 1 3/8 10 30
½ 3 11 35²
Note 1: These values may not be reported by some automated stations.
Note 2: Further values in increments of 5 statue mailes may be reported, i.e., 40, 45, 50, etc.
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Runway Visual Range Group (RDRDR/VRVRVRVRFT or RDRDR/VnVnVnVnVVxVxVxVxFT). The standards for observing and reporting Runway Visual Range (RVR) are described in Chapter 7.

  a. RVR shall be coded in the format RDRDR/VRVRVRVRFT,
     where R indicates that the runway number follows,
     DRDR is the runway number (an additional DR may
     be used for runway approach directions, such as R for
     right, L for left, and C for center), VRVRVRVR
     is the constant reportable value, and FT indicates that
     units of measurement are feet.  A solidus "/" without spaces
     separates the runway number from the constant reportable value.
     For example, an RVR value for runway 01L of 800 feet would be
     coded "R01L/0800FT".

  b. RVR that is varying shall be coded in the format,
     RDRDR/VnVnVnVnVVxVxVxVxFT, where R indicates that
     the runway number follows, DRDR is the runway number
     (an additional DR may be used for runway approach directions,
     such as R for right, L for left, and C for
     center), VnVnVnVn is the lowest reportable value in feet,
     V separates lowest and highest visual range values,
     VxVxVxVx is the highest reportable value, and FT
     indicates that units of measurement are feet.  A solidus "/"
     without spaces separates the runway number from the reportable
     values.  For example, the 10-minute RVR for runway 01L varying
     between 600 and 1,000 feet would be coded "R01L/0600V1000FT".

  c. The values shall be based on light setting 5 at manual stations
     regardless of the light setting actually in use (see Appendix D).
     RVR values shall be coded in increments of 100 feet up to 1,000
     feet, increments of 200 feet from 1,000 feet to 3,000 feet, and
     increments of 500 feet from 3,000 feet to 6,000 feet.  Manual
     RVR shall not be reported below 600 feet.  For automated stations,
     RVR may be reported from up to four designated runways.

  d. If the RVR is less than its lowest reportable value, the
     VRVRVRVR or VnVnVnVn groups shall be preceded by
     M.  If the RVR is greater than its highest reportable value,
     the VRVRVRVR or VxVxVxVx groups shall be preceded by
     a P.  For example, an RVR for runway 01L of less than 600
     feet will be coded "R01L/M0600FT"; an RVR for runway 27 of greater
     than 6,000 feet will be coded "R27/P6000FT".
Present Weather Group (w'w'). The standards for observing and reporting present weather are described in Chapter 8.

The appropriate notations found in Table 12-2 shall be used to code present weather.

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Table 12-2. Notations for Reporting Present Weather (See note 1)
QUALIFIERWEATHER PHENOMENA
INTENSITY OR
PROXIMITY
1
DESCRIPTOR

2
PRECIPITATION

3
OBSCURATION

4
OTHER

5
 - Light
   Moderate
   (see note 2)
 + Heavy
VC In the
   Vicinity
   (see note 3)
MI Shallow
PR Partial
BC Patches
DR Low Drifting
BL Blowing
SH Shower(s)
TS Thunderstorm
FZ Freezing
DZ Drizzle
RA Rain
SN Snow
SG Snow Grains
IC Ice Crystals
PE Ice Pellets
GR Hail
GS Small Hail
   and/or Snow
   Pellets
UP Unknown
   Precipitation
BR Mist
FG Fog
FU Smoke
VA Volcanic Ash
DU Widespread
   Dust
SA Sand
HZ Haze
PY Spray
PO Well-
   Developed
   Dust/Sand
   Whirls
SQ Squalls
FC Funnel Cloud
   Tornado
   Waterspout
   (see note 4)
SS Sandstorm
SS Duststorm
1. The weather groups shall be constructed by considering columns 1 to 5 in the table
   above in sequence, i.e. intensity, followed by description, followed by weather phenomena,
   e.g. heavy rain shower(s) is coded as +SHRA
2. To denote moderate intensity no entry or symbol is used.
3. See paragraph 8.4.1.a.(2), 8.5, and 8.5.1 for vicinity definitions.
4. Tornados and waterspouts shall be coded as +FC.
The following general rules apply when coding present weather for a METAR or SPECI:

Weather occurring at the point of observation (at the station) or in the vicinity of the station shall be coded in the body of the report; weather observed but not occurring at the point of observation (at the station) or in the vicinity of the station shall be coded in Remarks. With the exceptions of volcanic ash, low drifting dust, low drifting sand, low drifting snow, shallow fog, partial fog, and patches (of) fog, an obscuration shall be coded in the body of the report if the surface visibility is less than 7 miles or considered operationally significant. Volcanic ash shall always be coded when observed. Separate groups shall be used for each type of present weather. Each group shall be separated from the other by a space. METAR/SPECI shall contain no more than three present weather groups. The weather groups shall be constructed by considering columns 1 to 5 in Table 12-2 in sequence, i.e., intensity, followed by description, followed by weather phenomena, e.g., heavy rain shower(s) is coded as +SHRA.

  a. Intensity or Proximity Qualifier. 

      (1) Intensity shall be coded with precipitation types, except ice crystals and hail,
          including those associated with a thunderstorm (TS) and those of a showery nature
          (SH).  Tornadoes and waterspouts shall be coded as +FC.  No intensity 
          shall be ascribed to the obscurations of blowing dust (BLDU), blowing sand 
          (BLSA), and blowing snow (BLSN).  Only moderate or heavy intensity
          shall be ascribed to sandstorm (SS) and duststorm (DS).

      (2) The proximity qualifier for vicinity, VC, (weather phenomena observed in
          the vicinity of but not at the point(s) of observation) shall be coded in
          combination with thunderstorm (TS), fog (FG), shower(s) (SH),
          well-developed dust/sand whirls (PO), blowing dust (BLDU), blowing
          sand (BLSA), blowing snow (BLSN), sandstorm (SS), and
          duststorm (DS).  Intensity qualifiers shall not be coded with VC.

          VCFG shall be coded to report any type of fog in the vicinity of the
          point(s) of observation.

          Precipitation not occurring at the point of observation but within 10 statute
          miles shall be coded as showers in the vicinity (VCSH).

  b. Descriptor Qualifier.  Only one descriptor shall be coded for each weather
     phenomena group, e.g., "-FZDZ".  Mist (BR) shall not be coded with any
     descriptor.

     (1) The descriptors shallow (MI), partial (PR), and patches (BC)
         shall only be coded with FG, e.g., "MIFG".

     (2) The descriptors low drifting (DR) and blowing (BL) shall only
         be coded with dust (DU), sand (SA), and snow (SN), e.g.,
         "BLSN" or "DRSN".  DR shall be coded for DU, SA, or
         SN raised by the wind to less than six feet above the ground.

         When blowing snow is observed with snow falling from clouds, both phenomena are
         reported, e.g., "SN BLSN".  If there is blowing snow and the observer cannot
         determine whether or not snow is also falling, then BLSN shall be
         reported.  PY shall be coded only with blowing (BL).

     (3) The descriptor shower(s) (SH) shall be coded only with one or more
         of the precipitation types of rain (RA), snow (SN), ice
         pellets (PE), small hail (GS), or large hail (GR). 
         The SH descriptor indicates showery-type precipitation.  When
         any type of precipitation is coded with VC, the intensity and
         type of precipitation shall not be coded.

     (4) The descriptor thunderstorm (TS) may be coded by itself, i.e.,
         a thunderstorm without associated precipitation, or it may be coded
         with the precipitation types of rain (RA), snow (SN),
         ice pellets (PE), small hail and/or snow pellets (GS),
         or hail (GR).  For example, a thunderstorm with snow and small
         hail and/or snow pellets would be coded as "TSSNGS".  TS shall
         not be coded with SH.

     (5) The descriptor freezing (FZ) shall only be coded in combination
         with fog (FG), drizzle (DZ), or rain (RA), e.g.,
         "FZRA".  FZ shall not be coded with SH.

  c. Precipitation.  Up to three types of precipitation may be coded in
     a single present weather group.  They shall be coded in order of decreasing
     dominance based on intensity.

     (1) Drizzle shall be coded as DZ; rain shall be coded as RA;
         snow shall be coded as SN; snow grains shall be coded as
         SG; ice crystals shall be coded as IC; ice pellets shall
         be coded as PE, hail shall be coded as GR, and small hail
         and/or snow pellets shall be coded as GS.

     (2) At automated stations, precipitation of unknown type shall be coded as
         UP.

  d. Obscuration.

     (1) Mist shall be coded as BR; fog shall be coded as FG;
         smoke shall be coded as FU; volcanic ash shall be coded as
         VA; widespread dust shall be coded as DU; sand shall be
         coded as SA; and haze shall be coded as HZ

     (2) Shallow fog (MIFG), patches (of) fog (BCFG), and partial
         fog (PRFG) may be coded with prevailing visibility of 7 statute
         miles or greater.

     (3) Spray shall be coded only as BLPY.

  e. Other Weather Phenomena

     (1) Well-developed dust/sand whirls shall be coded as PO; squalls
         shall be coded as SQ; sandstorm shall be coded as SS;
         and duststorm shall be coded as DS.

     (2) Tornadoes and waterspouts shall be coded as +FC.  Funnel clouds
         shall be coded as FC.
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Sky Condition Group (NsNsNshshshs or VVhshshs or SKC/CLR). The standards for observing and reporting sky condition are described in Chapter 9.

  a. Sky condition shall be coded in the format, NsNsNshshshs, where
     NsNsNs is the amount of sky cover and hshshs is the height
     of the layer.  There shall be no space between the amount of sky cover
     and the height of the layer.  Sky condition shall be coded in an ascending
     order up to thefirst overcast layer.  At mountain stations, if the layer
     is below station level, the height of the layer shall be coded as ///.

  b. Vertical visibility shall be coded in the format, VVhshshs, where
     VV identifies an indefinite ceiling and hshshs is the vertical
     visibility into the indefinite ceiling (see paragraphs 9.4.4, 9.4.7, and
     9.5.5).  There shall be no space between the group identifier and the vertical
     visibility.

  c. Clear skies shall be coded in the format, SKC or CLR, where
     SKC is the abbreviation used by manual stations to indicate no
     layers are present and CLR is the abbreviation used by automated
     stations to indicate no layers are detected at or below 12,000 feet (see
     paragraph 9.5.4).
Each layer shall be separated from other layers by a space. The sky cover for each layer reported shall be coded by using the appropriate reportable contraction from Table 12-3. The report of clear skies (SKC or CLR) are complete layer reports within themselves. The abbreviations FEW, SCT, BKN, and OVC shall be followed, without a space, by the height of the layer.

Table 12-3. Contractions for Sky Cover
Reportable ContractionMeaningSummation Amount
of Layer
VV Vertical Visibility 8/8
SKC or CLR¹ Clear 0
FEW² Few 1/8 - 2/8
SCT Scattered 3/8 - 4/8
BKN Broken 5/8 - 7/8
OVC Overcast 8/8
1. The abbreviation CLR shall be used at automated stations when
   no layers at or below 12,000 feet are reported; the abbreviation
   SKC shall be used at manual stations when no layers are reported.
2. Any layer amount less than 1/8 is reported as FEW.
The height of the base of each layer, hshshs, shall be coded in hundreds of feet above the surface using three digits in accordance with Table 12-4.

Table 12-4. Increments of Reportable Values of Sky Cover Height
Range of Height Values (feet) Reportable Increment (feet)
<=5,000 To nearest 100
>5,000 but <=10,000 To nearest 500
>10,000 To nearest 1,000

At manual stations, cumulonimbus (CB) or towering cumulus (TCU) shall be appended to the associated layer. For example, a scattered layer of towering cumulus at 1,500 feet would be coded "SCT015TCU" and would be followed by a space if there were additional higher layers to code.

Temperature/Dew Point Group (T'T'/T'dT'd). The standards for observing and reporting temperature and dew point are given in Chapter 10. The temperature shall be separated from the dew point with a solidus "/".

The temperature and dew point shall be coded as two digits rounded to the nearest whole degree Celsius (see paragraph 2.6.3). For example, a temperature of 0.3C would be coded as "00". Sub-zero temperatures and dew points shall be prefixed with an M. For example, a temperature of 4C with a dew point of -2C would be coded as "04/M02"; a temperature of -0.5C would be coded as "M00".

If the temperature is not available, the entire temperature/dew point group shall not be coded. If the dew point is not available, the temperature shall be coded followed by a solidus "/" and no entry made for dew point. For example, a temperature of 1.5C and a missing dew point would be coded as "02/".

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Altimeter (APHPHPHPH). The standards for observing and reporting altimeter are described in Chapter 11.

The altimeter group always starts with an A (the international indicator for altimeter in inches of mercury). The altimeter shall be coded as a four digit group immediately following the A using the tens, units, tenths, and hundredths of inches of mercury. The decimal point is not coded.

Remarks (RMK)

Remarks shall be included in all METAR and SPECI, if appropriate.

Remarks shall be separated from the body of the report by a space and the contraction RMK. If there are no remarks, the contraction RMK is not required.

METAR/SPECI remarks fall into 2 categories: (1) Automated, Manual, and Plain Language (see paragraph 12.7.1), and (2) Additive and Maintenance Data (see paragraph 12.7.2).

Remarks shall be made in accordance with the following:

  a. Where plain language is called for, authorized contractions,
     abbreviations, and symbols should be used to conserve time and
     space.  However, in no case should an essential remark, of which
     the observer is aware, be omitted for the lack of readily available
     contractions.  In such cases, the only requirement is that the
     remark be clear.  For a detailed list of authorized contractions,
     see FAA Order 7340 Series, Contractions.

  b. Time entries shall be made in minutes past the hour if the time
     reported occurs during the same hour the observation is taken.
     Hours and minutes shall be used if the hour is different, or this
     Handbook prescribes the use of the hour and minutes.

  c. Present weather coded in the body of the report as VC may
     be further described, i.e., direction from the station, if known.
     Weather phenomena beyond 10 statute miles of the point(s) of
     observation shall be coded as distant (DSNT) followed by the
     direction from the station.  For example, precipitation of unknown
     intensity within 10 statute miles east of the station would be coded
     as "VCSH E"; lightning 25 statute miles west of the station would be
     coded as "LTG DSNT  W".

  d. Distance remarks shall be statute miles except for automated lightning
     remarks which are in nautical miles.

  e. Movement of clouds or weather, if known, shall be coded with respect
     to the direction toward which the phenomena is moving.  For example,
     a thunderstorm moving toward the northeast would be coded as "TS MOV NE".

  f. Directions shall use the eight points of the compass coded in a
     clockwise order.

  g. Insofar as possible, remarks shall be entered in the order they are
     presented in the following paragraphs.
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Automated, Manual, and Plain Language Remarks. These remarks generally elaborate on parameters reported in the body of the report. Automated and manual remarks may be generated either by an automated or manual station. Plain language remarks are only provided from manual stations.

  a. Volcanic Eruptions (Plain Language).  Volcanic eruptions shall be coded.  

     The remark shall be plain language and contain the following, if known:

     (1) Name of volcano.

     (2) Latitude and longitude or the direction and the approximate
         distance from the station.

     (3) Date/Time (UTC) of the eruption.

     (4) Size description, approximate height, and direction of
         movement of the ash cloud.

     (5) Any other pertinent data about the eruption.

         For example, a remark on a volcanic eruption would look like
         the following:

         MT. AUGUSTINE VOLCANO 70 MILES SW ERUPTED 231505 LARGE ASH CLOUD
         EXTENDING TO APRX 30000 FEET MOVING NE.

         Pre-eruption volcanic activity shall not be coded.  Pre-eruption
         refers to unusual and/or increasing volcanic activity which
         could presage a volcanic eruption.

  b. Funnel Cloud (Tornadic activity_B/E(hh)mm_LOC/DIR_(MOV)).  At
     manual stations, tornadoes, funnel clouds, or waterspouts shall be
     coded in the format,  Tornadic activity_B/E(hh)mm_LOC/DIR_(MOV),
     where TORNADO, FUNNEL CLOUD, orWATERSPOUT identifies the
     specific tornadic activity,  B/E denotes the beginning and/or
     ending time, (hh)mm is the time of occurrence (only the minutes
     are required if the hour can be inferred from the report time), LOC/DIR
     is the location and/or direction of the phenomena from the station,
     and MOV is the movement, if known (see paragraphs 8.3.3.c, 8.5.3.c,
     and 8.5.5.b).  Tornadic activity shall be coded as the first remark after
     the "RMK" entry.  For example, "TORNADO B13 6 NE" would indicate that a
     tornado, which began at 13 minutes past the hour, was 6 statute miles
     northeast of the station.

  c. Type of Automated Station (AO1 or AO2).  AO1 or AO2
     shall be coded in all METAR/SPECI from automated stations.  Automated
     stations without a precipitation discriminator shall be identified as
     AO1; automated station with a precipitation discriminator shall
     be identified as AO2.

  d. Peak Wind (PK_WND_dddff(f)/(hh)mm).  The peak wind shall be coded
     in the format,PK_WND dddff(f)/(hh)mm of the next METAR, where PK_WND
     is the remark identifier, ddd is the direction of the peak wind,
     ff(f) is the peak wind speed since the last METAR, and (hh)mm is
     the time of occurrence (only the minutes are required if the hour can be
     inferred from the report time) (see paragraphs 5.4.5 and 5.5.5).  There
     shall be a space between the two elements of the remark identifier and the
     wind direction/speed group; a solidus "/" (without spaces) shall
     separate the wind direction/speed group and the time.  For example, a peak
     wind of 45 knots from 280 degrees that occurred at 15 minutes past the hour
     would be coded "PK WND 28045/15".

  e. Wind Shift (WSHFT_(hh)mm).  A wind shift shall be coded in the format,
     WSHFT_(hh)mm, where WSHFT is the remark identifier and (hh)mm
     is the time the wind shift began (only the minutes are required if the hour
     can be inferred from the report time) (see paragraphs 5.4.6 and 5.5.6).  The
     contraction FROPA may be entered following the time if it is reasonably
     certain that the wind shift was the result of a frontal passage.  There shall
     be a space between the remark identifier and the time and, if applicable,
     between the time and the frontal passage contraction.  For example, a remark
     reporting a wind shift accompanied by a frontal passage that began at
     30 minutes after the hour would be coded as "WSHFT 30 FROPA".

  f. Tower or Surface Visibility (TWR_VIS_vvvvv or SFC_VIS_vvvvv).
     Tower visibility or surface visibility (see paragraphs 6.5.4 and 6.5.5)
     shall be coded in the formats, TWR_VIS_vvvvv or SFC_VIS_vvvvv,
     respectively, where vvvvv is the observed tower/surface
     visibility value.  A space shall be coded between each of the remark
     elements.  For example, the control tower visibility of 1 1/2 statute
     miles would be coded "TWR VIS 1 1/2".

  g. Variable Prevailing Visibility (VIS_vnvnvnvnvnVvxvxvxvxvx).
     Variable prevailing visibility shall be coded in the format
     VIS_vnvnvnvnvnVvxvxvxvxvx, where VIS is the remark
     identifier, vnvnvnvnvn is the lowest visibility evaluated,
     V denotes variability between two values, and vxvxvxvxvx
     is the highest visibility evaluated.  There shall be one space following
     the remark identifier; no spaces between the letter V and the
     lowest/highest values.  For example, a visibility that was varying
     between 1/2 and 2 statute miles would be coded "VIS 1/2V2" (see
     paragraphs 6.4.5 and 6.5.3).

  h. Sector Visibility (VIS_[DIR]_vvvvv) [Plain Language].  The
     sector visibility shall be coded in the format, VIS_[DIR]_vvvvv,
      where VIS is the remark identifier, [DIR] defines
     the sector to 8 points of the compass, and vvvvv is the sector
     visibility in statute miles, using the appropriate set of values in
     Table 12-1 (see paragraphs 6.4.6 and 6.5.7).  For example, a visibility
     of 2 1/2 statute miles in the northeastern octant would be
     coded "VIS NE 2 1/2".

  i. Visibility At Second Location (VIS_vvvvv_[LOC]).  At designated
     automated stations, the visibility at a second location shall be coded
     in the format VIS_vvvvv_[LOC], where VIS is the remark
     identifier, vvvvv is the measured visibility value, and [LOC]
     is the specific location of the visibility sensor(s) at the station (see
     paragraph 6.5.6).  This remark shall only be generated when the condition
     is lower than that contained in the body of the report.  For example, a
     visibility of 2 1/2 statute miles measured by a second sensor located at
     runway 11 would be coded "VIS 2 1/2 RWY11".

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  j. Lightning (Frequency_LTG(type)_[LOC]).

     (1) When lightning is observed at a manual station, the frequency,
         type of lightning, and location shall be reported.  The remark
         shall be coded in the format Frequency_LTG(type)_[LOC].
         The contractions for the type and frequency of lightning shall
         be based on Table 12-5.  The location and direction shall be coded
         in accordance with paragraph 12.7.c.  For example, "OCNL LTGICCG OHD",
         "FRQ LTG VC", or "LTG DSNT W".

     (2) When lightning is detected by an automated system:

         (a) Within 5 nautical miles of the Airport Location Point (ALP),
             it will be reported as TS in the body of the report
             with no remark;

         (b) Between 5 and 10 nautical miles of the ALP, it will be reported
             as VCTS in the body of the report with no remark;

         (c) Beyond 10 but less than 30 nautical miles of the ALP, it will
             be reported in remarks only as LTG DSNT followed by the
             direction from the ALP.
Table 12-5. Type and Frequency of Lightning
Type of Lightning
TypeContractionDefinition
Cloud-ground CG Lightning occurring between cloud and ground.
In-cloud IC Lightning which takes place within the cloud.
Cloud-cloud CC Streaks of lightning reaching from one cloud to another.
Cloud-air CA Streaks of lightning which pass from a cloud to air,
but do not strike the ground.
Frequency of Lightning
FrequencyContractionDefinition
Occasional OCNL Less than 1 flash/minute.
Frequent FRQ About 1 to 6 flashes/minute.
Continuous CONS More than 6 flashes/minute.

  k. Beginning and Ending of Precipitation (w'w'B(hh)mmE(hh)mm).
     At designated stations, the beginning and ending of precipitation
     shall be coded in the format, w'w'B(hh)mmE(hh)mm, where w'w'
     is the type of precipitation, B denotes the beginning, E
     denotes the ending, and (hh)mm is the time of occurrence (only the
     minutes are required if the hour can be inferred from the report time)
    (see paragraph 8.5.5.a).  There shall be no spaces between the elements.
     The coded remarks are not required in SPECI and should be reported in
     the next METAR.  Intensity qualifiers shall not be coded.  For example,
     if rain began at 0005, ended at 0030, and snow began at 0020, and ended
     at 0055, the remarks would be coded "RAB05E30SNB20E55". If the precipitation
     were showery, the remark would be coded "SHRAB05E30SHSNB20E55".

  l. Beginning and Ending of Thunderstorms (TSB(hh)mmE(hh)mm).  The
     beginning and ending of thunderstorm(s) shall be coded in the format,
     TSB(hh)mmE(hh)mm, where TS indicates thunderstorm, B
     denotes the beginning, E denotes the ending, and (hh)mm
     is the time of occurrence (only the minutes are required if the hour can be
     inferred from the report time) (see paragraph 8.5.4).  There shall be no
     spaces between the elements.  For example, if a thunderstorm began at 0159
     and ended at 0230, the remark would be coded "TSB0159E30".

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  m. Thunderstorm Location (TS_LOC_(MOV_DIR)) [Plain Language].
     Thunderstorm(s) shall be coded in the format, TS_LOC_(MOV_DIR),
     where TS identifies the thunderstorm activity, LOC is the
     location of the thunderstorm(s) from the station, and MOV_DIR is
     the movement with direction, if known (see paragraph 8.4.1.b(5) and 8.5.4).
     For example, a thunderstorm southeast of the station and moving toward the
     northeast would be coded "TS SE MOV NE".

  n. Hailstone Size (GR_[size]) [Plain Language].  At designated
     stations, the hailstone size shall be coded in the format, GR_[size],
     where GR is the remark identifier and [size] is the
     diameter of the largest hailstone.  The hailstone size shall be coded in
     1/4 inch increments (see paragraph 8.5.1.c(8)).  For example, "GR 1 3/4"
     would indicate that the largest hailstones were 1 3/4 inches in diameter.
     If GS is coded in the body of the report, no hailstone size remark
     is required.

  o. Virga (VIRGA_(DIR)) [Plain Language].  Virga shall be coded
     in the format, VIRGA_(DIR), where VIRGA is the remark
     identifier and DIR is the direction from the station.  The
     direction of the phenomena from the station is optional, e.g., "VIRGA"
     or "VIRGA SW".

  p. Variable Ceiling Height (CIG_hnhnhnVhxhxhx).  The variable
     ceiling height shall be coded in the format, CIG_hnhnhnVhxhxhx,
     where CIG is the remark identifier, hnhnhn is the
     lowest ceiling height evaluated, V denotes variability between
     two values, and hxhxhx is the highest ceiling height evaluated
     (see paragraph 9.5.7 and Table 9-1). There shall be one space
     following the remark identifier; no spaces between the
     letter V and the lowest/highest ceiling values.  For example,
     "CIG 005V010" would indicate a ceiling that was varying between 500
     and 1,000 feet.

  q. Obscurations (w'w'_[NsNsNs]hshshs). [Plain Language]
     Obscurations (surface-based or aloft) shall be coded in the format,
     w'w'_[NsNsNs]hshshs, where w'w' is the weather causing
     the obscuration at the surface or aloft, NsNsNs is the applicable sky
     cover amount of the obscuration aloft (FEW, SCT, BKN, OVC) or at the
     surface (FEW, SCT, BKN), and hshshs is the applicable height
     (see paragraphs 9.4.3 and 9.5.6). Surface-based obscurations shall have
     a height of "000".  There shall be a space separating the weather
     causing the obscuration and the sky cover amount; there shall be no space
     between the sky cover amount and the height.  For example, fog hiding
     3-4 oktas of the sky would be coded "FG SCT000"; a broken layer at 2,000 feet
     composed of smoke would be coded "FU BKN020".

  r. Variable Sky Condition (NsNsNs(hshshs)_V_NsNsNs). [Plain Language]
     The variable sky condition remark shall be coded in the format,
     NsNsNs(hshshs)_V_NsNsNs, where NsNsNs(hshshs) and NsNsNs
     identifies the two operationally significant sky conditions and V denotes
     the variability between the two ranges (see paragraphs 9.4.2.d and 9.5.9).
     If there are several layers with the same sky condition amount, the layer
     height (hshshs) of the variable layer shall be coded.  For example,
     a cloud layer at 1,400 feet that is varying between broken and overcast would
     be coded "BKN014 V OVC".

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  s. Significant Cloud Types [Plain Language].  The significant cloud
     type remark shall be coded in all reports in the following manner (see
     paragraphs 9.4.6 and 9.5.10):

     (1) Cumulonimbus or Cumulonimbus Mammatus (CB or CBMAM_LOC_(MOV_DIR).
         Cumulonimbus or cumulonimbus mammatus, as appropriate, (for which no
         thunderstorm is being reported) shall be coded in the format, CB or
         CBMAM_LOC_(MOV_DIR), where CB or CBMAM is the cloud
         type, LOC is the direction from the station, and MOV_DIR is
         the movement with direction (if known).  The cloud type, location, movement,
         and direction entries shall be separated from each other with a space.
         For example, a CB up to 10 statute miles west of the station moving
         toward the east would be coded "CB W MOV E".  If the CB was more than
         10 statute miles to the west, the remark would be coded "CB DSNT W".

     (2) Towering cumulus (TCU_[DIR]).  Towering cumulus clouds shall be
         coded in the format, TCU_[DIR], where TCU is the cloud
         type and DIR is the direction from the station.  The cloud type
         and direction entries shall be separated by a space.  For example, a
         towering cumulus cloud up to 10 statute miles west of the station would
         be coded "TCU W".

     (3) Altocumulus castellanus (ACC_[DIR]).  Altocumulus castellanus
         shall be coded in the format, ACC_[DIR], where ACC is
         the cloud type and DIR is the direction from the station.  The
         cloud type and direction entries shall be separated by a space.  For
         example, an altocumulus cloud 5 to 10 statute miles northwest of the
         station would be coded "ACC NW".

     (4) Standing lenticular or Rotor clouds (CLD_[DIR]).  Stratocumulus
         (SCSL), altocumulus (ACSL), or cirrocumulus (CCSL), or rotor clouds shall
         be coded in the format, CLD_[DIR], where CLD is the cloud
         type and DIR is the direction from the station.  The cloud type
         and direction entries shall be separated by a space.  For example,
         altocumulus standing lenticular clouds observed southwest through west
         of the station would be coded  "ACSL SW-W"; an apparent rotor cloud 5 to
         10 statute miles northeast of the station would be coded "APRNT ROTOR CLD
         NE"; and cirrocumulus clouds south of the station would be coded "CCSL S".

  t. Ceiling Height at Second Location (CIG_hhh_[LOC]).   At
     designated stations, the ceiling height at a second location shall be
     coded in the format, CIG_hhh_[LOC], where CIG is the remark
     identifier,  hhh is the measured height of the ceiling, and [LOC]
     is the specific location of the ceilometer(s) at the station (see paragraph
     9.5.8).  This remark shall only be generated when the ceiling is lower than
     that contained in the body of the report.  For example, if the ceiling
     measured by a second sensor located at runway 11 is broken at 200 feet,
     the remark would be "CIG 002RWY11".

  u. Pressure Rising or Falling Rapidly (PRESRR/PRESFR).  At designated
     stations, when the pressure is rising or falling rapidly at the time of
     observation (see paragraphs 11.4.6 and 11.5.5), the remark PRESRR
     (pressure rising rapidly) or PRESFR (pressure falling rapidly) shall
     be included in the report.

  v. Sea-Level Pressure (SLPppp).  At designated stations, the sea-level
     pressure shall be coded in the format SLPppp, where SLP is
     the remark identifier and ppp is the sea-level pressure in
     hectopascals (see paragraphs 11.4.4 and 11.5.4).  For example, a sea-level
     pressure of 998.2 hectopascals would be coded as "SLP982".  For a METAR, if
     sea-level pressure is not available, it is coded as "SLPNO".

  w. Aircraft Mishap (ACFT_MSHP) [Plain Language].  If a report is
     taken to document weather conditions when notified of an aircraft mishap,
     the remark ACFT_MSHP shall be coded in the report but not transmitted.
     The act of non-transmission shall be indicated by enclosing the remark in
     parentheses in the record, i.e., "(ACFT MSHP)".

  x. No SPECI Reports Taken (NOSPECI) [Plain Language].  At manual
     stations where SPECI's are not taken, the remark NOSPECI shall
     be coded to indicate that no changes in weather conditions will be
     reported until the next METAR.

  y. Snow Increasing Rapidly (SNINCR_[inches-hour/inches on ground]).
     At designated stations, the snow increasing rapidly remark shall be
     reported, in the next METAR, whenever the snow depth increases by 1 inch
     or more in the past hour.  The remark shall be coded in the format,
     SNINCR [inches-hour/inches on ground], where SNINCR is the
     remark indicator, inches-hour is the depth increase in the past hour,
     and inches on ground is the total depth of snow on the ground at
     the time of the report.  The depth increase in the past hour and the total
     depth on the ground are separated from each other by a solidus "/".
     For example, a snow depth increase of 2 inches in the past hour with a
     total depth on the ground of 10 inches would be coded "SNINCR 2/10".

  z. Other Significant Information [Plain Language].  Agencies may
     add to a report other information significant to their operations, such
     as information on fog dispersal operations, runway conditions, "FIRST"
     or "LAST" report from station, etc.
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Additive and Automated Maintenance Data. Additive data groups are only reported at designated stations. The maintenance data groups are only reported from automated stations.

  a. Precipitation

     (1) Amount of Precipitation.  The amount of liquid precipitation
         shall be coded as the depth of precipitation that accumulates in an
         exposed vessel during the time period being evaluated.  The amount
         of freezing or frozen precipitation shall be the water equivalent of
         the solid precipitation accumulated during the appropriate time period.

     (2) Units of Measure for Precipitation.  Precipitation measurements
         shall be in inches, tenths of inches, or hundredths of inches
         depending on the precipitation being measured (see Table 12-6).
Table 12-6. Units of Measure of Precipitatiom
Type of MeasurementUnit of Measure
Liquid Precipitation 0.01 inch
Water Equivalent of Solid Precipitation 0.01 inch
Solid Precipitation 0.1 inch
Snow Depth 1.0 inch
     (3) Depth of Freezing or Frozen Precipitation.  The depth
         of freezing and/or frozen precipitation shall be the actual
         vertical depth of the precipitation accumulated on a horizontal
         surface during the appropriate time period (see paragraphs 12.7.2.a(3)(b)
         and 12.7.2.a(3)(c).  If snow falls, melts, and refreezes, the
         depth of ice formed shall be included in the measurement.

         (a) Hourly Precipitation Amount (Prrrr).  At designated
             automated stations, the hourly precipitation amount shall
             be coded in the format, Prrrr, where P is the
             group indicator and rrrr is the water equivalent of all
             precipitation that has occurred since the last METAR (see
             paragraph 12.7.2.a(1)).  The amount shall be coded in
             hundredths of an inch.  For example, "P0009" would indicate
             9/100 of an inch of precipitation fell in the past hour; "P0000"
             would indicate that less than 1/100 of an inch of precipitation
             fell in the past hour.

             The group shall be omitted if no precipitation occurred since the
             last METAR.

         (b) 3- and 6-Hour Precipitation Amount (6RRRR).  At designated
             stations, the 3- and 6-hourly precipitation group shall be coded
             in the format, 6RRRR, where 6 is the group indicator
             and RRRR is the amount of precipitation.  The amount of
             precipitation (water equivalent) accumulated in the past 3 hours
             shall be reported in the 3-hourly report; the amount accumulated
             in the past 6 hours shall be reported in the 6-hourly report.  The
             amount of precipitation shall be coded in inches, using the tens,
             units, tenths and hundredths digits of the amount.  When an
             indeterminable amount of precipitation has occurred during the
             period, RRRR shall be coded 6////.  For example, 2.17 inches
             of precipitation would be coded "60217".  A trace shall be
             coded "60000".

         (c) 24-Hour Precipitation Amount (7R24R24R24R24).  At
             designated stations, the 24-hour precipitation amount shall be
             coded in the format, 7R24R24R24R24, where 7 is the
             group indicator and R24R24R24R24 is the 24-hour precipitation
             amount. The 24-hour precipitation amount shall be included in the
             1200 UTC (or other agency designated time) report whenever more
             than a trace of precipitation (water equivalent) has fallen in the
             preceding 24 hours.  The amount of precipitation shall be coded by
             using the tens, units, tenths, and hundredths of inches (water
             equivalent) for the 24-hour period.  If more than a trace (water
             equivalent) has occurred and the amount cannot be determined, the
             group shall be coded 7////.  For example, 1.25 inches of
             precipitation (water equivalent) in the past 24 hours shall be
             coded "70125".

         (d) Snow Depth on Ground (4/sss).  At designated stations,
             the total snow depth on the ground group shall be coded in the
             0000 and 1200 UTC observation whenever there is more than a trace
             of snow on the ground.  It shall be coded in the 0600 and 1800 UTC
             observation if there is more than a trace of snow on the ground
             and more than a trace of precipitation (water equivalent) has
             occurred within the past 6 hours.  The remark shall be coded in
             the format, 4/sss, where 4/ is the group indicator
             and sss is the snow depth in whole inches using three digits.
             For example, a snow depth of 21 inches shall be coded as "4/021".

         (e) Water Equivalent of Snow on Ground (933RRR).  At
             designated stations, the water equivalent of snow on the ground
             shall be coded each day, in the 1800 UTC report, if the average
             snow depth is 2 inches or more.  Theremark shall be coded in the
             format, 933RRR, where 933 is the group indicator
             and RRR is the water equivalent of snow, i.e., snow, snow
             pellets, snow grains, ice pellets, ice crystals, and hail, on
             the ground.  The water equivalent shall be coded in tens, units,
             and tenths of inches, using three digits.  If the water equivalent
             of snow consists entirely of hail, the group shall not be coded.
             A water equivalent of 3.6 inches of snow would be coded as "933036";
             a water equivalent of 12.5 would be coded as "933125".

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  b. Cloud Types (8/CLCMCH).  At designated stations, the group,
     8/CLCMCH, shall be reported and coded in 3- and 6-hourly reports
     when clouds are observed.  The predominant low cloud (CL), middle
     cloud (CM), and high cloud (CH), shall be identified in
     accordance with the WMO International Cloud Atlas, Volumes I and II,
     or the WMO Abridged International Cloud Atlas or agency observing
     aids for cloud identification.  A 0 shall be coded for the low,
     middle, or high cloud type if no cloud is present in that classification.
     A solidus "/" shall be coded for layers above an overcast.  If no
     clouds are observed due to clear skies, the cloud type group shall not
     be coded.  For example, a report of "8/6//" would indicate an overcast
     layer of stratus clouds; a report of "8/903" would indicate cumulonimbus
     type low clouds, no middle clouds, and dense cirrus high clouds.

  c. Duration of Sunshine (98mmm).  The duration of sunshine that
     occurred the previous calendar day shall be coded in the 0800 UTC report.
     If the station is closed at 0800 UTC, the group shall be coded in the
     first 6-hourly METAR after the station opens.  The duration of sunshine
     shall be coded in the format, 98mmm, where 98 is the group
     indicator and mmm is the total minutes of sunshine.  The minutes
     of sunshine shall be coded by using the hundreds, tens, and units digits.
     For example, 96 minutes of sunshine would be coded "98096".  If no
     sunshine occurred, the group would be coded "98000".

  d. Hourly Temperature and Dew Point (TsnT'T'T'snT'dT'dT'd).  At
     designated stations, the hourly temperature and dew point group shall
     be coded to the tenth of a degree Celsius in the format, TsnT'T'T'snT'dT'dT'd,
     where T is the group indicator, sn is the sign of the temperature,
     T'T'T' is the temperature, and T'dT'dT'd is the dew point
     (see paragraphs 10.5.1 and 10.5.3).  The sign of the temperature and
     dew point shall be coded as 1 if the value is below 0°C and 0 if the value
     is 0°C or higher.  The temperature and dew point shall be reported
     in tens, units, and tenths of degrees Celsius.  There shall be no spaces
     between the entries.  For example, a temperature of 2.6°C and dew
     point of -1.5°C would be reported in the body of the report as
     "03/M01" and the TsnT'T'T'snT'dT'dT'd group as "T00261015".  If
     dew point is missing report the temperature; if the temperature is missing
     do not report the temperature/dew point group.

  e. 6-Hourly Maximum Temperature (1snTxTxTx).  At designated
     stations, the 6-hourly maximum temperature group shall be coded in the
     format, 1snTxTxTx, where 1 is the group indicator, sn
     is the sign of the temperature, TxTxTx is the maximum temperature
     in tenths of degrees Celsius using three digits (see paragraphs 10.4.4,
     10.5.2, and 10.5.3).  The sign of the maximum temperature shall be coded
     as 1 if the maximum temperature is below 0°C and 0 if the maximum
     temperature is 0°C or higher.  For example, a maximum temperature
     of -2.1°C would be coded "11021"; 14.2°C would be coded "10142".

  f. 6-Hourly Minimum Temperature (2snTnTnTn).  At designated stations,
     the 6-hourly minimum temperature group shall be coded in the format,
     2snTnTnTn, where 2 is the group indicator, sn is the
     sign of the temperature, and TnTnTn is the minimum temperature in
     tenths of degrees Celsius using three digits (see paragraphs 10.4.4,
     10.5.2, and 10.5.3).  The sign of the minimum temperature shall be coded
     as 1 if the minimum temperature is below 0°C and 0 if the minimum
     temperature is 0°C or higher.  For example, a minimum temperature
     of -0.1°C would be coded "21001"; 1.2°C would be coded "20012".

  g. 24-Hour Maximum and Minimum Temperature (4snTxTxTxsnTnTnTn).  At
     designated stations, the 24-hour maximum temperature and the 24-hour
     minimum temperature shall be coded in the format, 4snTxTxTxsnTnTnTn,
     where 4 is the group indicator, sn is the sign of the
     temperature, TxTxTx is the maximum 24-hour temperature, and TnTnTn
     is the 24-hour minimum temperature (see paragraphs 10.4.4, 10.5.2, and
     10.5.3).  TxTxTx and TnTnTn shall be coded in tenths of
     degrees Celsius using three digits.  The sign of the maximum or minimum
     temperature shall be coded as 1 if it is below 0°C and 0 if it
     is 0°C or higher.  For example, a 24-hour maximum temperature of
     10.0°C and a 24-hour minimum temperature of -1.5°C would be coded
     "401001015"; a 24-hour maximum temperature of 11.2°C and a 24-hour
     minimum temperature of 8.4C would be coded as"401120084".

  h. 3-Hourly Pressure Tendency (5appp).  At designated stations, the
     3-hourly pressure tendency group shall be coded in the format, 5appp,
     where 5 is the group indicator, a is the character of
     pressure change over the past 3 hours (see Table 12-7), and ppp
     is the amount of barometric change in tenths of hectopascals (see Table 12-8).
     The amount of barometric change shall be coded using the tens, units, and
     tenths digits (see paragraphs 11.4.7 and 11.5.4).  For example, a steady
     increase of 3.2 hectopascals in the past three hours would be coded "52032".
Table 12-7. Characteristics of Barometer Tendency
Primary
Requirement
Description Code
Figure
Atmospheric
pressure now
higher than 3
hours ago.
Increasing, then decreasing. 0
Increasing, then steady, or increasing then
increasing more slowly.
1
Increasing steadily or unsteadily. 2
Decreasing or steady, then increasing; or
increasing then increasing more rapidly.
3
Atmospheric
pressure now
same as 3 hours
ago.
Increasing, then decreasing. 0
Steady 4
Decreasing then increasing. 5
Atmospheric
pressure now
lower than 3
hours ago.
Decreasing, then increasing. 5
Decreasing, then steady, or decreasing then
decreasing more slowly.
6
Decreasing steadily or unsteadily. 7
Steady or increasing, then decreasing; or
decreasing then decreasing more rapidly.
8
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Table 12-8. 3-Hour Pressure Change
Amount of Barometric Change (Rise or Fall) in the Past 3 hours "ppp"
Code
Figure
Inches of
Mercury
Hectopascals Code
Figure
Inches of
Mercury
Hectopascals Code
Figure
Inches of
Mercury
Hectopascals
000
002
003
005
007
008
010
012
014
015
017
019
020
022
024
025
027
029
030
032
034
036
037
039
041
042
044
046
047
049
051
052
054
056
058
059
061
063
064
066
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
0.050
0.055
0.060
0.065
0.070
0.075
0.080
0.085
0.090
0.095
0.100
0.105
0.110
0.115
0.120
0.125
0.130
0.135
0.140
0.145
0.150
0.155
0.160
0.165
0.170
0.175
0.180
0.185
0.190
0.195
0.0
0.2
0.3
0.5
0.7
0.8
1.0
1.2
1.4
1.5
1.7
1.9
2.0
2.2
2.4
2.5
2.7
2.9
3.0
3.2
3.4
3.6
3.7
3.9
4.1
4.2
4.4
4.6
4.7
4.9
5.1
5.2
5.4
5.6
5.8
5.9
6.1
6.3
6.4
6.6
068
069
071
073
075
076
078
080
081
083
085
086
088
090
091
093
095
097
098
100
102
103
105
107
108
110
112
113
115
117
119
120
122
124
125
127
129
130
132
134
0.200
0.205
0.210
0.215
0.220
0.225
0.230
0.235
0.240
0.245
0.250
0.255
0.260
0.265
0.270
0.275
0.280
0.285
0.290
0.295
0.300
0.305
0.310
0.315
0.320
0.325
0.330
0.335
0.340
0.345
0.350
0.355
0.360
0.365
0.370
0.375
0.380
0.385
0.390
0.395
6.8
6.9
7.1
7.3
7.5
7.6
7.8
8.0
8.1
8.3
8.5
8.6
8.8
9.0
9.1
9.3
9.5
9.7
9.8
10.0
10.2
10.3
10.5
10.7
10.8
11.0
11.2
11.3
11.5
11.7
11.9
12.0
12.2
12.4
12.5
12.7
12.9
13.0
13.2
13.4
135
137
139
141
142
144
146
147
149
151
152
154
156
157
159
161
163
164
166
168
169
171
173
174
176
178
179
181
183
185
186
188
190
191
193
195
196
198
200
201
0.400
0.405
0.410
0.415
0.420
0.425
0.430
0.435
0.440
0.445
0.450
0.455
0.460
0.465
0.470
0.475
0.480
0.485
0.490
0.495
0.500
0.505
0.510
0.515
0.520
0.525
0.530
0.535
0.540
0.545
0.550
0.555
0.560
0.565
0.570
0.575
0.580
0.585
0.590
0.595
13.5
13.7
13.9
14.1
14.2
14.4
14.6
14.7
14.9
15.1
15.2
15.4
15.6
15.7
15.9
16.1
16.3
16.4
16.6
16.8
16.9
17.1
17.3
17.4
17.6
17.8
17.9
18.1
18.3
18.5
18.6
18.8
19.0
19.1
19.3
19.5
19.6
19.8
20.0
20.1
  i. Sensor Status Indicators.  Sensor status indicators should be
     reported as indicated below:

     (1) if the Runway Visual Range should be reported but is missing,
         RVRNO shall be coded.

     (2) when automated stations are equipped with a present weather
         identifier and that sensor is not operating, the remark PWINO
         shall be coded.

     (3) when automated stations are equipped with a tipping bucket
         rain gauge and that sensor is not operating, PNO shall
         be coded.

     (4) when automated stations are equipped with a freezing rain
         sensor and that sensor is not operating, the remark FZRANO
         shall be coded.

     (5) when automated stations are equipped with a lightning detection
         system and that sensor is not operating, the remark TSNO
         shall be coded.

     (6) when automated stations are equipped with a secondary visibility
         sensor and that sensor is not operating, the remark VISNO_LOC
         shall be coded.

     (7) when automated stations are equipped with a secondary ceiling height
         indicator and that sensor is not operating, the remark CHINO_LOC
         shall be coded.

  j. Maintenance Indicator.  A maintenance indicator sign, $,
     shall be coded when an automated system detects that maintenance is
     needed on the system.
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RADAR OBSERVATION (FFAA) CODE

FFAA.  Radar Observation indicator.
 a.  FF.  Land based radar, GG. Sea based radar.
 b.  AA.  Tropical Cyclone information, BB.  significant weather information.

DTG.  Date Time Group.  DDHHm.  
 a.  DD.  Day of the month in two digits.
 b.  HH.  Zulu hour.
 c.  m.  Minute tens digit (09=1 for 10 minutes, 22=2 for 20 minutes, etc)

Station.  IIiii.  WMO block and station number.
 a.  II.  WMO block.
 b.  iii.  Station number.

Lat.  4WvLaLaLa.  Latitude group.
 a.  4.  Indicator for the group.
 b.  Wv. Wave length of radar. 
 c.  LaLaLa  Latitude to the nearest tenth of a degree.

Long.  QcLoLoLoLo.  Longitude group.
 a.  Qc.  Quadrant of the globe
    1 = N and E
    3 = S and E
    5 = S and W
    7 = N and W
 b.  LoLoLoLo.  Longitude to the nearest tenth of a degree.

Char.  Coded characteristics of the eye of the system.
  Ac--Accuracy of the position of the center or the eye of the 
    tropical cyclone.
      Code
      Fig.
       1  Eye visible on radar scope, accuracy good (within 10km).
       2  Eye visible on radar scope, accuracy fair (within 30 km).
       3  Eye visible on radar scope, accuracy poor (within 50 km).
       4  Position of the center within the area covered by the radar scope, 
              determination by means of the spiral-band overlay, accuracy good
              (within 10km).
       5  Position of the center within the area covered by the radar scope, 
              determination by means of the spiral-band overlay, accuracy fair
              (within 30km).
       6  Position of the center within the area covered by the radar scope, 
              determination by means of the spiral-band overlay, accuracy poor
              (within 50km).
       7  Position of the center outside the area covered by the radar scope,
              extrapolation by means of the spiral-band overlay.
       /  Accuracy undetermined.
 
  Sc--Shape and definition of the eye of the tropical cyclone.
      Code
      Fig.
       0  Circular.
       1  Elliptical-the minor axis at least 3/4 the length of the major axis.
       2  Elliptical-the minor axis is less than 3/4 the length of the major axis.
       3  Apparent double eye.
       4  Other shape.
       5  Ill defined.
       /  Undetermined.

  Wc--Diameter or length of axis of the eye of the tropical cyclone.
      Code
      Fig.
       0  Less than 5 km.
       1   5 to less than 10 km.
       2  10 to less than 15 km.
       3  15 to less than 20 km.
       4  20 to less than 25 km.
       5  25 to less than 30 km.
       6  30 to less than 35 km.
       7  35 to less than 40 km.
       8  40 to less than 50 km.
       9  50 km and greater.
       /  Undetermined.

  ac--Change in character of the eye during the past 30 minutes preceding
    the time of observation.
      Code
      Fig.
       0  Eye has first become visible during the past 30 minutes.
       1  No significant change in characteristics or size of the eye.
       2  Eye has become smaller with no other significant change in characteristics.
       3  Eye has become larger with no other significant change in characterisitcs.
       4  Eye has become less distinct with no significant change in size.
       5  Eye has become less distinct and decreased in size.
       6  Eye has become less distinct and increased in size.
       7  Eye has become more distinct with no significant change in size.
       8  Eye has become more distinct and decreased in size.
       9  Eye has become more distinct and increased in size.
       /  Change in character and size of eye cannot be determined.

  rt--Distance between the end of the outermost spiral band and the  
    center of the tropical cyclone.
      Code
      Fig.
       0    0 to less than 100 km.
       1  100 to less than 200 km.
       2  200 to less than 300 km.
       3  300 to less than 400 km.
       4  400 to less than 500 km.
       5  500 to less than 600 km.
       6  600 to less than 800 km.
       7  800 km or more.
       /  Doubtful or undetermined.

Mvmnt.  tedsdsfsfs.  Movement of the system.
 a.  te.  Time interval for which the system has been evaluated.
 b.  dsds.  The direction in tens of degrees toward which the system is moving.
 c.  fsfs.  The speed in knots at which the system is moving.
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AUSTRALIAN TROPICAL OBSERVATION CODE

Sid...Storm Identifier.

Stnam...Storm Name

Dtg...Date. 01 is the Year 2001, 11 is the Month November, and 27 is the day of the month.

HHmm...Hours and Minutes of the observation.

Lat...Latitude to the nearest tenth of a degree.

Long...Longitude to the nearest tenth of a degree.

Dir...Direction of movement.

Sm/s...Speed of movement in meters per second.

ChPa...Central Pressure in Hectopascals- 990 (hPa).

OhPa...Pressure of the outermost closed isobar in Hectopascals- 1008 (hPa)

Rout...Radius of outermost closed isobar in Kilometers: 0450 (450km)

Max...Maximum Wind in meters per second: 20(m/s)

Rad...Radius of maximum wind in kilometers: 200 (km)

30NE...Radius of 15m/s (30knot) winds to the NE

30SE...Radius of 15m/s (30 knot) winds to the SE

30SW...Radius of 15m/s (30 knot) winds to the SW

30NW...Radius of 15m/s (30 knot) winds to the NW

SD...Storm Depth: D

(S=shallow<700hPa; M=medium 200-400hPa; D=Deep(>400hPa)

RECCO CODE

Symbolic Form of the mandatory data:

9XXX9...The 9's on either end of this group are simply indicator numbers. The XXX is normally 777, which means the aircraft has radar capability, or 222, which means the radar is not working.

GGggI...GG is the hour of the report; gg is the minute of the report, in "Zulu" or Greenwich Mean Time, on a 24-hour clock. Zulu is 5 hours later than Central Daylight Savings Time, so a time of 2208Z translates to 1708 CDT or 5:08 p.m. CDT.
I is an indicator regarding aircraft height and dewpoint sensing capability.
0..No dewpoint capability / aircraft below 10000 meters
1..No dewpoint capability / acft at or abv 10000 meters
2..No dewpoint cap / acft blo 10000 m / fl temp blo -50C
3..No dewpoint cap / acft aoa 10000 m / fl temp blo -50C
4..Dewpoint capability / aircraft below 10000 meters
5..Dewpoint capability / acft at or above 10000 meters
6..Dewpoint cap / acft below 10000 m / fl temp blo -50C
7..Dewpoint cap / acft aoa 10000 m / fl temp blo -50C

YQLaLaLa
Y is the day of the week..Sunday=1...Saturday=7
Q is the quadrant of the globe the aircraft is located:
0..0-90N / 0-90W
1..0-90N / 90W-180
2..0-90N / 180-90E
3..0-90N / 90E-0
4..Not used
5..0-90S / 0-90W
6..0-90S / 90W-180
7..0-90S / 180-90E
8..0-90S / 90E-0
LaLaLa is the latitude in tenths of degrees. 268 would be 26.8 degrees. To find out if it is 26.8 North or 26.8 South, you need to look back at Q, the second digit in this data group (normally 0 or 1).

LoLoLoBf
LoLoLo is the longitude of the aircraft in tenths of degrees.
880 would be 88.0 degrees, 110 would be 11.0 or 111.0
depending on the quadrant of the globe indicator in the last group.
West or East is also determined by Q in the previous data group.
B..Turbulence group as follows..
0..No turbulence
1..Moderate turbulence..in clear air..infrequent
2..Moderate turbulence..in clear air..frequent
3..Moderate turbulence..in cloud..infrequent
4..Moderate turbulence..in cloud..frequent
5..Severe turbulence..in clear air..infrequent
6..Severe turbulence..in clear air..frequent
7..Severe turbulence..in cloud..infrequent
8..Severe turbulence..in cloud..frequent
f..Conditions along route of flight as follows..
0..In the clear
8..In and out of clouds
9..In clouds all the time
/..Impossible to determine due to darkness or other cause.

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hhhdtda
hhh gives the pressure altitude of the aircraft to the nearest decameter. For example 305 is 305 decameters = 305 meters = 10,007 feet
dtda..gives information about how the winds were calculated, as follows:
dt specifies if the wind is "0" Spot wind; "1" Average wind; or " / " meaning no wind report. Almost always a "spot wind"
da specifies how the winds were obtained. "0"-Winds obtained using doppler radar or inertial systems (almost always); "1"-Winds obtained using other navigation equipment / techniques "/"-Unable to determine wind or wind not compatible.

ddfff
Wind direction and speed at the flight level of the aircraft.
dd= true wind direction to the nearest 10 degrees, where 00=winds from the north 09=090 degrees=east, 18=180 degrees=south, 27=270 degrees=west
fff=wind speed in knots. To convert to miles per hour, multiply by 1.15

TTTdTdw
TT is the temperature in Celsius. If the temperature is negative, 50 is added to the absolute value of the temperature, and any hundreds digits are omitted. For example, a temperature of -12 would be coded as 62 (12+50 = 62) To determine if a temperature of "10" is really +10 or -110, see the indicator number in the time group above. Missing temperatures are coded as //.
TdTd is the dewpoint at flight level. Dewpoints are encoded the same as temperature. When the dewpoint is colder than -49.4C, it is reported as // and a plain language remark is added with the actual dewpoint, i.e. DEW POINT M53C. // is also reported if the dewpoint is too dry to measure accurately, or missing.
w is the present weather group with the following meanings. The largest number is used if more than one type of weather is present.
0..Clear
1..Scattered clouds
2..Broken clouds
3..Overcast / Undercast
4..Fog, thick dust or haze
5..Drizzle
6..Rain (continuous or intermittent from stratoform clouds)
7..Snow, or rain and snow mixed
8..Rain (continuous or intermittent from cumuliform clouds)
9..Thunderstorm
/..Unknown for any cause, including darkness

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/jHHH...
/ is an indicator for this group
j is the code for the level being reported by HHH in this group. The code is as follows...
0..Sea level pressure in millibars (1000's omitted)
1..200 mb level in geopotential decameters (1000s omitted)
2..850 mb level in geopotential meters (1000's omitted)
3..700 mb level in geopotential meters (1000's omitted)
4..500 mb level in geopotential decameters
5..400 mb level in geopotential decameters
6..300 mb level in geopotential decameters
7..250 mb level in geopotential decameters (1000s omitted)
8..D-value in geopotential decameters (if negative, 500 is added to HHH)
9..925 mb level in geopotential meters
HHH..Geopotential height or sea level pressure of the level specified in the j indicator just above.

Of the optional data, about the only extra group you are likely to see are surface winds, if the aircraft is flying at or below 10,000 feet. We'll show you how to decode surface winds here, then the rest of the RECCO code will be explained at the very end of this page.

4ddff
4 is the indicator that surface wind data follows
dd is the wind direction to the nearest ten degrees. 50 is added is the wind is over 100 kts, so a wind of 220 degrees at 10 knots will be coded as 42210, while a wind of 220 degrees at 110 knots will be coded as 47210.
ff is the wind speed in knots. Wind speeds above 130 kts are not coded, because the sea becomes covered by a solid sheet of spray and it is impossible to determine if the winds are 140 knots or 160 knots, etc: it all looks the same.

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OPTIONAL DATA:

1kNsNsNs ChhHH ..... ..... 4ddff 6WsSsWdd 7IrItSbSe 7hhHH 8ddSrOe 8EwElci 9ViTwTwTw

1kNsNsNs
1 is the indicator for clouds.
k is the total number of different clouds observed. You need to know this so you can tell when all the cloud groups end, and the next optional data groups begin.
Ns is the amount of coverage of the most significant cloud, in eighths.
Ns is the eighths coverage of the second most significant cloud
Ns is the eighths coverage of the third most significant cloud

ChhHH
C is the cloud type corresponding to the first Ns reported above, coded as follows:
0..cirrus
1..cirrocumulus
2..cirrostratus
3..altocumulus
4..altostratus
5..nimbostratus
6..stratocumulus
7..stratus
8..cumulus
9..cumulonimbus
/..Cloud type unknown due to darkness or other phenomena.
hh is the base (height of the bottom edge) of the cloud,
If the number is below 50, the height is in hundreds of feet, i.e. 34 is 3400 feet
Numbers coded between 51 and 55 are not used.
Numbers coded between 56 and 79 are in thousands of feet after 50 is subtracted from the number, i.e. 62 is a base of 12,000 ft (62-50=12)
HH is the height of the top of the cloud using the same decode as the base.

NOTE: AT THIS POINT THERE WILL BE A FIVE NUMBER CLOUD GROUP (CHsHsHtHt) FOR EACH CLOUD LAYER AS INDICATED IN THE 1kNsNsNs GROUP. IF THERE ARE MORE THAN THREE LAYERS OF CLOUDS, THE FIRST THREE ChhHH GROUPS WILL BE FOLLOWED BY ANOTHER 1kNsNsNs GROUP, WHERE "k" NOW SHOWS HOW MANY CLOUD LAYERS ARE LEFT.

6WsSsWddw
6 is the group indicator for significant and distant weather
Ws gives any significant weather changes as listed in the following table:
0..No change
1..Marked wind shift
2..Beginning or ending of marked turbulence
3..Marked temperature change (non-altitude)
4..Precipitation begins or ends
5..Change in cloud forms
6..Fog or ice fog begins or ends
7..Warm front
8..Cold front
9..Front, type not specified
Ss is the distance of occurence of Ws above, where
0..No report
1..Previous position
2..Present position
3..30 nm
4..60 nm
5..90 nm
6..120 nm
7..150 nm
8..180 nm
9..More than 180 nm
Wd is the distant weather (more than 30 miles away), where
0..No report
1..Signs of a tropical cyclone
2..Ugly threatening sky
3..Duststorm or sandstorm
4..Fog or ice fog
5..Waterspout
6..Cirrostratus shield or bank
7..Altostratus / altocumulus shield or bank
8..Line of heavy cumulus
9..Cumulonimbus heads or thunderstorms
dw is the bearing of Wd above, where
0..No report
1..NE 2..E 3..SE 4..S 5..SW 6..W 7..NW 8..N 9..All directions

7IrItSbSe
7 is the icing group indicator. Icing is reported in two groups, this and the next.
Ir is the rate of icing, where
7..Light 8..Moderate 9..Severe / Unknown or contrails
It is the type of icing, where
0..None
1..Rime ice in clouds
2..Clear ice in clouds
3..Mixed ice in clouds
4..Rime ice in precipitation
5..Clear ice in precipitation
6..Mixed ice in precipitation
7..Frost (icing in clear air)
8..Nonpersistent contrails (under 1/4 nm long)
9..Persistent contrails
Sb is the bearing to beginning of ice, using the same table as dw above
Se is the bearing to ending of ice, using the same table as dw above

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7hhHH
7 is the icing group indicator. This is the second group of the icing group pair.
hh is the base of the icing, the same format as that used to report cloud bases hshs noted previously
HH is the top of the icing, the same format as that used to report cloud bases hshs noted previously

8drdrSrOe
8 is the radar group indicator. There are two groups to report radar.
drdr is the bearing (direction) of the echo center in tens of degrees, where 00 is north, 09 is east, 18 is south, and 27 is west.
Sr is the distance to echo center, where
0..0 nm
1..10 nm
2..20 nm
3..30 nm
4..40 nm
5..50 nm
6..60-80 nm
7..80-100 nm
8..100-150 nm
9..Greater than 150 nm
/..Unknown
Oe is the orientation of echo, where
0..Circular 1..NNE-SSW 2..NE-SW 3..ENE-WSW 4..E-W 5..ESE-WNW 6..SE-NW 7..SSE-NNW 8..S-N /..Unknown

8EwElceie
8 is the echo indicator group. This is the second group of the radar code.
Ew is the echo width or diameter using the same format as Sr above
El is the length of major axis using the same format as Sr above
ce is the character of the echo, where
1..Scattered area 2..Solid area 3..Scattered line 4..Solid line 5..Scattered all quadrants 6..Solid, all quads /..Unknown
ie is the intensity of the echo, where
2..Weak 5..Moderate 8..Strong /..Unknown


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DROPSONDE CODE

PART ALPHA (A)

XXAA – Identifier for a temp drop code

 YYGGId
  Identifier: YY – Date Group
  Identifier: GG – Time Group
  Identifier: Id - The highest mandatory level for which wind is available

LATTITUDE: 99LaLaLa
  Identifier: 99 – Indicator for data on position follows
  Identifier: LaLaLa – Latitude in tenths of degrees

LONGITUDE: QcLoLoLoLoc – The octant of the globe
  Identifier: LoLoLoLo – Longitude in
    tenths of degrees

MARSDEN SQUARE: MMMUlaUlo
  Identifier and explain: MMM – Marsden square
  Identifier and explain: UlaUlo – Units digits in the reported
    latitude and longitude

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SEA LEVEL PRESSURE: 99PoPoPo ToToToDoDo
dodofofofo
  Identifier: 99 – Indicator for data at the surface level follows
  Identifier: PoPoPo – Indicator for pressure of
    specified levels in whole millibar (thousands digit omitted)
  Identifier: ToToTo – Tens and digits of air
    temperature (not rounded off) in degrees Celsius, at specified levels beginning with
    surface
  Identifier: DoDo – Dewpoint depression at standard isobaric
    surfaces beginning with surface level



NOTE

        When the depression is 4.9C or less the units and tenths digits
        of the depression are encoded. Depressions of 5.0 through 5.4C are
        encoded as 50. Depressions of 5.5C through 5.9C are encoded as 56.
        Dew point depressions of 6.0 and above are encoded in tens and units
        with 50 added. Dew point depressions for relative humidities less then
        20% are encoded as 80. When air temperature is below –40C report
        DaDaas //


  Identifier: dodo – True direction from which the wind is
    blowing rounded to nearest 5 degrees. Report hundreds and tens digits. The unit (0 and 5)
    is added to the hundreds digit of wind.
  Identifier: fofofo – Wind speed in knots. Hundreds
    digit is sum of hundreds digit of speed and unit digit of direction. Example: 295 degrees
    at 125 knots is encoded as 29625

STANDARD ISOBARIC SURFACES: P1P1h1h1h1
T1T1T1D1D1 d1d1f1f1f1
  Identifier: P1P1 – Pressure of standard isobaric surfaces in
    units of tens of millibars. (1000mbs = 00, 925mbs = 92, 850mbs = 85, 700mbs = 70, 500mbs =
    50, 400mbs = 40, 300mbs = 30, 250mbs = 25)
  Identifier: h1h1h1 – Heights of the standard
    pressure level in geopotential meters or decameters above the surface. Encoded in
    decameters at and above 500mbs omitting, if necessary, the thousands or tens of thousands
    digits. Add 500 to hhh for negative 1000mb or 925mb heights. Report 1000mb group as 00///
    ///// ///// when pressure is less than 950mbs.
  Identifier: T1T1T1D1D1 –
    Same temperature/dew point encoding procedures apply to all levels
  Identifier: d1d1f1f1f1 –
    Same wind encoding procedures apply to all levels

DATA FOR TROPOPAUSE LEVELS: 88PnPnPn TnTnTnDnDn
dndnfnfnfn
  Identifier: 88 – Indicator for Tropopause level follows
  Identifier: PnPnPn – Pressure at the tropopause
    level reported in whole millibars. Report 88PnPnPn as
    88999 when tropopause is not observed
  Identifier: TnTnTnDnDn –
    Same temperature/dew point encoding procedures apply
  Identifier: dndnfnfnfn - Same
    wind encoding procedures apply

MAXIMUM WIND DATA: 77PnPnPn dndnfnfnfn
4vbvbvava
  Identifier: 77 – Indicator that data for maximum wind level and for vertical wind
    shear follow when max wind does not coincide at flight. If the maximum wind level
    coincides with flight level encode as 66
  Identifier: PnPnPn – Pressure at maximum wind
    level in whole millibars
  Identifier: dndnfnfnfn –
    Same wind encoding procedures apply
  Identifier: 4 – Data for vertical wind shear follow
  Identifier: vbvb – Absolute value of vector difference
    between max wind and wind 3000 feet BELOW the level of max wind, reported to the nearest
    knot. Use "//" if missing and a 4 is reported. A vector difference of 99 knots
    or more is reported with the code figure "99".
  Identifier: vava – Absolute value of vector difference
    between max wind and wind 3000 feet ABOVE the level of max wind, reported to the nearest
    knot. Use "//" if missing and a 4 is reported. A vector difference of 99 knots
    or more is reported with the code figure "99".

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AIRCRAFT AND MISSION IDENTIFICATION: 61616 AFXXX XXXXX XXXXX OB X KXXX
  Identifier: 61616 – Aircraft and mission identification data follows
  Identifier: AFXXX – The identifier AF for U.S. Air Force and the last three digits
    of the aircraft’s tail number
  Identifier: XXXXX XXXXX – The identifier for the type of mission being flown.

    If a training mission the mission identifier is WXWXA TRAIN. The fifth letter
        "A" is the only character that could possibly change. The "A" defining
        that the flight is in the Atlantic basin. The letter "C" identifies the Central
        Pacific area and the letter "E" identifies the Eastern Pacific.
      If an operational storm mission: the first two numbers Identifies the number of times an
        aircraft has flown this system and the second two numbers identifies the system number.
        The last character again identifies the basin flown. The name of the storm would replace
        TRAIN. EXAMPLE: AF968 0204A BONNIE – Aircraft 50968, this was the second flight into
        this system and the system was the fourth of the season. The system reached tropical storm
        strength and was named BONNIE.
    
Identifier: OB 04 – The observation (both vertical and horizontal) number as
    transmitted from the aircraft.


NATIONALLY DEVELOPED CODES: 62626
  Identifier: 62626 – This is the remarks section. Only the remarks: EYE EYEWALL XXX
    (eyewall will be followed by the radian to the eye center procured from the ARWO), or
    RAINBAND, if release was made in a feeder band. The splash location will be recorded
    automatically by computer. Followed by last wind height in meters and the mean boundary
    layer wind with degrees to the nearest five-degree and knots.

PART BRAVO (B) XXBB – Identifier for a temp drop code Date/Time Group: YYGG8 Identifier: YY – Date Group Identifier: GG – Time Group Identifier: 8 - Indicator group for the use of satellite navigation for windfinding

LATTITUDE: 99LaLaLa Identifier: 99 – Indicator for data on position follows Identifier: LaLaLa – Latitude in tenths of degrees

LONGITUDE: QcLoLoLoLo Identifier: Qc – The octant of the globe Identifier: LoLoLoLo – Longitude in tenths of degrees

MARSDEN SQUARE: MMMUlaUlo Identifier and explain: MMM – Marsden square Identifier and explain: UlaUlo – Units digits in the reported latitude and longitude

SEA LEVEL PRESSURE: 00PoPoPo ToToToDoDo Identifier: 00 – Indicator for data at the surface level follows Identifier: PoPoPo – Indicator for pressure of specified levels in whole millibars (thousands digit omitted) Identifier: ToToTo – Tens and digits of air temperature (not rounded off) in degrees Celsius, at specified levels beginning with surface Identifier: DoDo – Dewpoint depression at standard isobaric surfaces beginning with surface level

NOTE

When the depression is 4.9C or less the units and tenths digits of the depression are encoded. Depressions of 5.0 through 5.4C are encoded as 50. Depressions of 5.5C through 5.9C are encoded as 56. Dew point depressions of 6.0 and above are encoded in tens and units with 50 added. Dew point depressions for relative humidities less then 20% are encoded as 80. When air temperature is below –40C report DaDaas //

SIGNIFICANT ISOBARIC LEVELS: nonoPoPoPo ToToToDoDo Identifier: nono – Number of level starting with surface level. Only surface will be numbered as "00". When a standard level is also selected as significant, repeat the level. Identifier: PoPoPo – Pressure at specified levels in whole millibars. Identifier: ToToToDoDo – Same temperature/dew point encoding applies.

SOUNDING SYSTEM INDICATION, RADIOSONDE/SYSTEM STATUS, LAUNCH TIME: 31313 srrarasasa 8GGgg Identifier: srrarasasa – Sounding system indicator, radiosonde/system status Identifier: sr – Solar and infrared radiation correction ( 0 – no correction) Identifier: rara Radiosonde/sounding system used (96 – Descending radiosonde) Identifier: sasa – Tracking technique/status of system used (08 – Automatic satellite navigation) Identifier: 8GGgg – Launch time Identifier: 8 – Indicator group Identifier: GG – Time in hours Identifier: gg – Time in minutes Top of Page
ADDITIONAL DATA GROUPS: 51515 101XX 0PnPnPnPn
Identifier: 51515 – Additional data in regional code follow Identifier: 10166 – Geopotential data are doubtful between the following levels 0PnPnPnPn. This code figure is used only when geopotential data are doubtful from one level to another. Identifier: 10167 – Temperature data are doubtful between the following levels 0PnPnPnPn. This code figure shall be reported when only the temperature data are doubtful for a portion of the descent. If a 10167 group is reported a 10166 will also be reported. EXAMPLE: Temperature is doubtful from 540mbs to 510mbs. SLP is 1020mbs. The additional data groups would be : 51515 10166 00251 10167 05451 Identifier: 10190 – Extrapolated altitude data follows:

    When the sounding begins within 25mbs below a standard surface, the height of the surface is reported in the format 10190 PnPnhnhnhn. The temperature group is not reported. EXAMPLE: Assume the release was made from 310mbs and the 300mb height was 966 decameters. The last reported standard level in Part A is the 400mb level. The data for the 300mb level is reported in Part A and B as 10190 30966 When the sounding does not reach surface, but terminates within 25mbs of a standard surface, the height of the standard surface is reported in Part A of the code in standard format and also at the end of Part A and Part B of the code in the format as 10190 PnPnhnhnhn. EXAMPLE: Assume termination occurred as 980mbs and the extrapolated height of the 1000mb level was 115 meters. The 1000mb level would be reported in Part A of the code as 00115 ///// ///// and in Part B as 10190 0015.
Identifier: 10191 – Extrapolated surface pressure preceds. Extrapolated surface pressure is only reported when the termination occurs between 850mbs and the surface. Surface pressure is reported in Part A as 99PoPoPo ///// and in Part B as 00PoPoPo /////. When surface pressure is extrapolated the 10191 group is the last additional data group reported in Part B.

61616, 62626 – Same procedures as Part A
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VORTEX REPORT CODE

MESSAGE HEADER. The first line of the message is the code used to identify a vortex message in various meteorological data bases, followed by the date and time (Zulu) the message was transmitted.

A. DATE AND TIME OF FIX. The time when the center of the storm was located or "fixed". 05/1237Z means the report is from the fifth day of the month, at 1237Z. "Z" means Zulu time, or Greenwich Mean Time (CDT + 5 hrs). Therefore, 1237Z = 7:37 a.m. Central Daylight Savings Time.

<B. LATITUDE AND LONGITUDE of the vortex fix in degrees and minutes.
Example: 30 DEG 59 MIN N 77 DEG 16 MIN W.
Use this information to plot up the latest location of the storm center; comparing the current position to previous positions gives the latest movement of the storm. But be aware that sometimes storms "wobble", or make sharp turns, so listen to the latest National Hurricane Center forecasts if you want to know where the storm might be headed next!

C. MINIMUM HEIGHT AT STANDARD LEVEL. Standard level refers to certain "slices" of the atmosphere used by meteorologists around the world. The exact altitude of each of these slices relates to the pressure. The lower this height is below the "standard" height indicates how low the pressure is inside the hurricane; stronger storms have lower pressures. The number reported is in meters. Hurricane Hunters fly storms at the "surface" (500 to 1500 feet above the water), 925 millibars (2500 feet or 762 meters), 850 mb (4780 ft or 1457 m), or 700 mb (9880 ft or 3011 m). The aircraft will fly using an autopilot set to follow a constant pressure altitude. For example, when flying a mission at 700 mb, the aircraft's pressure altimeter will read 9,880 feet all day. But as the plane flies into lower pressure, the plane will actually be flying closer to the ground. A radar altimeter bounces radar pulses off the ground and tells the crew how high they actually are, and the meteorologist uses this number to calculate the height of standard surface. In the example above, the 700 millibar height was 2695 meters, which is 316 meters lower than the standard height of 3011 meters: a significant low pressure! When flying low-level (below 1500 feet) this block is reported as NA (Not Applicable).

D. ESTIMATE OF MAXIMUM SURFACE WIND OBSERVED IN KNOTS. 65 kt means the highest estimated surface wind is 65 knots on this particular inbound leg. The flight meteorologist looks at the sea surface and can estimate how strong the winds are by what the sea looks like. At particular wind speeds, the sea begins to form white caps, then patches of foam, then some of the foam patches begin to appear green, etc. The key word here is "observed"; the meteorologist may not see the highest surface winds because of darkness, heavy rain or clouds, so often this number is lower than the maximum flight level wind. A "knot" is a nautical mile (nm) per hour. To convert to miles per hour, use 1.15 miles/nm; 65 nm/hr x 1.15 mi/nm = 75 miles per hour. To convert to meters per second, cut knots in half: 65 kt = 33 m/s. If not observed at all, this block is reported as NA (Not Applicable).

E. BEARING AND RANGE FROM CENTER OF THE MAXIMUM SURFACE WIND given in degrees and nautical miles. The "bearing" is the direction from the center in which the surface wind was seen, reported in degrees (similar to compass headings, except these bearings are in reference to "true" instead of "magnetic" north). Due north is 0 degrees, east is 90 degrees, south is 180 degrees, and west is 270 degrees. The bearing in the example is 050 degrees, which means the surface wind was seen northeast of the center. To pinpoint where this was, you also need to know how far away it was: the "range". In this case, the 65 knot wind reported in part D was found 80 nautical miles (92 statute miles) northeast of the center.

F. MAXIMUM FLIGHT LEVEL WIND NEAR STORM CENTER. The highest wind seen on the last 100 mile leg inbound to the storm. There may be stronger winds in other sections of the storm (see remarks in Item P). These winds are at flight level, and were measured directly by the aircraft's instruments. In the example, the peak wind was 313 degrees 78 knots, which means the wind was blowing from a direction of 313 deg (northwest) at a speed of 78 kts (using the 1.15 mph/kt conversion, that's 90 miles per hour). Together with pressure (Items C and H), winds give an idea of how strong the storm currently is.

G. BEARING AND RANGE FROM CENTER OF MAXIMUM FLIGHT LEVEL WIND. Same method as reporting bearing and range for the surface winds (see Item E, above). In this example, the 78 knot flight level wind reported in Item F was found 063 degrees (northeast) of the center, and 32 nautical miles from the center. Usually the strongest winds are found in the "eyewall" surrounding the eye, and this gives an idea of how large the center (or eye) of the storm is.

H. MINIMUM SEA LEVEL PRESSURE computed from dropsonde or extrapolation. This is one of the key pieces of information which tell how strong the storm is. "Standard" sea level pressure is 1013 millibars. Since hurricanes, tropical storms, and tropical depressions are all low-pressure systems, the pressure reported here is almost always lower than standard. The lower the pressure, the more intense the storm. The word "EXTRAP" precedes any pressures extrapolated from aircraft sensor information; if the word "EXTRAP" is not there, it means the pressure was measured directly by a dropsonde released from the aircraft, and is usually more accurate. This lowest pressure is found in the center of the storm. Millibars can be converted to inches of Mercury using 0.0295 in-Hg/mb. In the example, the pressure of 954 mb is approximately 28.14 in-Hg. For reference, developing storms may have pressures around 1007 mb, most hurricanes are below 980 mb, and the lowest pressure measured in an Atlantic/Gulf of Mexico hurricane was 888 mb (Hurricane Gilbert). There may be small fluctuations in pressure due to normal, daily pressure rises and falls.

I. MAXIMUM FLIGHT LEVEL TEMPERATURE / PRESSURE ALTITUDE OUTSIDE THE EYE. This gives an idea of the general temperature surrounding the storm. "Standard" temperature at 700 mb (where we fly most hurricanes) is about -5 degrees Celsius, but in the tropics, it's usually 10 to 15 degrees warmer than "standard". What you especially want to look for is how it compares to the temperature inside the eye, in Item J or P. The example shows a temperature of 11 degrees Celsius (52 degrees Fahrenheit) at an altitude of 3082 meters (10,112 feet). The altitude is included because the airplane bumps up and down due to turbulence and other factors, and minor changes in the temperature may be due to changes in altitude.

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J. MAXIMUM FLIGHT LEVEL TEMPERATURE / PRESSURE ALTITUDE INSIDE THE EYE. This is yet another indicator of how "healthy" the storm is. One of the unusual features of a hurricane is that it is warmer inside the eye than outside. What you want to look for here is how much warmer it is than the temperature reported outside the eye in Item "I." A developing storm may be only a degree warmer inside the center, while a strong hurricane may be 10 degrees warmer. In this example, the eye temperature of 15 degrees Celsius (59 degrees Fahrenheit) is four degrees warmer than the temperatures immediately outside the eye. Be sure to look at the remarks in Item "P" to see if there was an even warmer temperature found inside the eye (but more than 5 miles from the fix position). The aircraft was at a pressure altitude of 3108 meters (10,198 feet).

K. DEWPOINT TEMPERATURE / SEA SURFACE TEMPERATURE INSIDE THE EYE. This is the "dewpoint" measured in the center of the storm. Dewpoint is a measure of the humidity. If the dewpoint and the temperature are exactly the same, the humidity is 100%. The formula for converting to relative humidity is too complicated to explain here, but the lower the dewpoint is, compared to the air temperature, the drier the air. In the example, the dewpoint was 13 Celsius (compared to a temperature of 15 Celsius), for a relative humidity of 87%. If the humidity is at or near 100%, it may mean the center is filled with clouds near the altitude of the aircraft, while a "healthy" hurricane may have a clear, drier eye. The second part of Item K is no longer used, as the aircraft do not carry the infrared sensors needed to measure sea surface temperature.

L. EYE CHARACTER. This is a brief description of what the eye looks like on radar. "CLOSED WALL" if the eye is completely surrounded by a ring of thunderstorms: the wall cloud. "OPEN NE" means there is a break in the wall to the northeast, etc. If the eye is not at least 50% surrounded by a wall cloud, this item and Item M will be reported as "NA" (Not Applicable).

M. EYE SHAPE ORIENTATION AND DIAMETER. Eye shapes are coded as follows: C-circular; CO-concentric; E-elliptical. Orientation of major axis of ellipse is transmitted in tens of degrees, and all diameters are transmitted in nautical miles. Example: E09/15/5 means elliptical eye oriented with major axis thru 90 degrees (and also 270 degrees), with length of major axis 15 nm, and length of minor axis 5 nm. CO8-14 means concentric eye with inner eye diameter 8 miles, and outer diameter 14 miles. The "healthiest" hurricanes usually have a small, circular eye. A concentric eye (a ring inside a ring) is a relatively rare phenomenon that may signal a temporary weakening while the storm reorganizes. An eye diameter that shrinks (compared to the previous vortex message) may signal strengthening: just as a twirling ice skater spins faster as she pulls in her arms, a hurricane may "spin" faster as its eye gets smaller. Eye diameters are usually 10-20 nautical miles, while we sometimes see them as small as 5 nm to as large as 60 nm.

N. FIX DETERMINED BY / FIX LEVEL. The first string of numbers indicates what the meteorologist used to find the center of the storm, using numbers 1 through 5, as follows:
1-Penetration, 2-Radar, 3-Wind, 4-Pressure, 5-Temperature.
After the solidus ("/"), you'll find one or two numbers which show at what level(s) the center was found, as follows:
0-surface, 1-1500 ft, 8-850 mb, 7-700 mb, 5-500 mb, 4-400 mb, 3-300 mb, 2-200 mb, 9-925 mb.
Example: 1235/7 means the fix was determined by four means: penetration, radar, winds, and pressure. The fix was made at 700 mb (approx 10,000 feet). If a calm spot was seen on the surface of the water, the fix level could have been "07" to indicated the surface and the 700 mb center were found within 5 nm of each other.

O. NAVIGATION FIX ACCURACY / METEOROLOGICAL ACCURACY. These numbers give an estimate of how accurate the position is. "Navigation accuracy" is a gauge of how well the navigation equipment is operating. The "Meteorological Accuracy" depends on how well the storm center can be defined by the meteorological data: if there is a sudden, sharp wind shift, and the temperature peak and pressure drop all coincide, the met accuracy will be a small number. A weaker storm will probably have a larger met accuracy. Both numbers are reported in nautical miles.

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P. REMARKS SECTION. Always starts with the Mission ID:
MISSION IDENTIFIER. The first line of the remarks is a unique identifier for each mission:
AFXXX AABBC NAME
Agency: Either AF for the Air Force Reserve Hurricane Hunters or NOAA for the National Oceanic and Atmospheric Agency aircraft
XXX: Tail number of the aircraft
AA: Total number of missions flown on this storm system
BB: Depression number (or "XX" if it's not a depression or greater)
C: Ocean basin. "A"=Atlantic, "C"=Central Pacific, "E"=Eastern Pacific
NAME: Storm name, or words CYCLONE (for depression) or INVEST. Example: AF984 1606A FRAN means Air Force Reserve aircraft number 984 is flying the 16th mission on Hurricane Fran, which is the 6th tropical cyclone of the season in the Atlantic/Gulf/Carribbean.

The flight meteorologist may add details of anything he or she feels are interesting to note. There are some standard remarks: "MAX FL WIND 105 KT NE QUAD 1051Z" reminds the public that while the highest wind seen just prior to hitting the center this time around was 78 knots (Item F), a stronger wind was seen earlier in the flight: 105 knots at 1051Z (5:51 a.m. CDT), in the northeast quadrant of the storm. Another standard remark is given anytime a temperature peak is seen more than 5 nm from the center location: "MAX FL TEMP 17C 130/10 NM FROM FL CENTER" says the highest temperature seen at flight level ("FL") was 17 Celsius, located 10 nautical miles in a direction of 130 degrees (to the southeast). Finally, the meteorologist lets you know Fran has a "STADIUM EFFECT", a rare but lovely phenomenon in which the clouds form a solid wall all around the eye, and stretch up and outward to reveal a circle of clear sky above, similar to a football stadium that's 50,000 feet tall! Take the cyberflight if you would like to see some pictures of the stadium effect.
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VORTEX DATA CODE


URPA14 is the name of this report. Pacific reports are coded URPA14
PGTW is the location of the recipient of the message (Joint Typhoon Warning Center)
DDTTTT is the day and time of the report in Greenwich Mean Time
AA is the Agency providing the report. AF is Air Force, NOAA is NOAA
### is the aircraft number flying the mission
MM is the number of the mission for this storm
XX is the depression number, or simply XX if not a depression or greater
NAME is the name of the storm, if any, or words CYCLONE or INVEST

LaLaLa is the latitude of the report in degrees/tenths

LoLoLoLo is the longitude of the report in degrees/tenths

jHHH is the pressure height data in the following format:
j=0 means sea level data follows with HHH in whole millibars
j=2 means 850 mb data follows with HHH in geopotential meters
j=3 means 700 mb data follows with HHH in geopotential meters
j=8 D - Value in geopotential decameters; if neg, 500 is added to HHH
j=9 means 925 mb data follows with HHH in geopotential meters

TTTdTd is the temperature/dewpoint in degrees Celcius.  If the temperature or
dewpoint is greater than 50, it means it is negative.  Subtract 50 from the number
and add a negative sign to decode.  Example: TdTd=58 decodes to -8 Celsius.

ddfff is the true direction of flight level wind in tens of degrees, and fff is
the speed of wind in knots (multiply by 1.15 to convert to miles per hour).
/ means data unknown or unobtainable

MF means that maximum flight level wind data follows, in the following format:
MFLaLaLa MLoLoLoLo MF fff.  The first two blocks are the latitude and
longitude of the max wind, in degrees and tenths.  The last block is the windspeed
in knots.

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Automatic Met Report from an Aircraft


YYGG--Day and Hour of the report.

ipipip--Phase of the Flight Indicator.  This indicator
     shows both the phase of the flight (unsteady, level, ascent or descent) and, in the case of level flight,
     the type of observation (routine or maximum wind).

IA...IA--Aircraft Identifier.

LaLaLaLaA--Latitude.
     LaLaLaLaA--Latitude in degrees and minutes.
     A--Direction of latitude (N or S).

LoLoLoLoLoB--Longitude.
     LoLoLoLoLo--Longitude in degrees and minutes.
     B--Direction of longitude (E or W).

GGgg--Time of observation in hours and minutes.

ShhIhIhI--Pressure altitude in hundreds of feet.

SSTATATA--Air temperature.
     SS--Sign of the temperature (PS = Plus or positive, MS = Minus or negative temperatures).
     TATATA--Air temperature, in tenths of a degree Celsius, at the level given
     by hIhIhI.

{SSTdTdTd or UUU}--Dew Point Temperature or Relative Humidity
     (either one or the other is given).
     SSTdTdTd--Dew Point Temperature.
         SS--Sign of the Dew Point Temperature (same as temperature).
         TdTdTd--Dew Point temperature, in tenths of degrees Celsius.
     UUU--Relative Humidity of the air in percent (first digit is always 0 unless 100% humidity).

ddd/fff--Winds.
     ddd--True direction in whole degrees, from which the wind is blowing.
     fff--Wind speed, in knots, at the level indicated by hIhIhI.

TBBA--Turbulence.

SS1S2S3--System information.
     S1--Type of navigation system.
     S2--Type of system used.
     S3--Temperature precision.

333--Indicator for data on pressure altitude and maximum derived equivalent vertical
     gust follow.

Fhdhdhd--Pressure Altitude as reported by ACARS systems.

VGfgfgfg--Maximum derived equivalent vertical gust,
     in meters per second.

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