JTWC Northern Indian Ocean Best Track Data


Click on a year link in the left-hand column to view or download Best Track data files for Northern Indian Ocean tropical cyclones for that year. Note that the Northern Indian Ocean covers both the Bay of Bengal and Arabian Sea basins. Data are available as individual storm text files and yearly compressed files (zip format).

Note: 1945-1970 data files have not been reviewed or updated for y2k and there are no storm or year notes for those years.

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    Northern Indian Ocean
     1945 IO List & zip
     1946 IO List & zip
     1947 IO List & zip
     1948 IO List & zip
     1949 IO List & zip
     1950 IO List & zip
     1951 IO List & zip
     1952 IO List & zip
     1953 IO List & zip
     1954 IO List & zip
     1955 IO List & zip
     1956 IO List & zip
     1957 IO List & zip
     1958 IO List & zip
     1959 IO List & zip
     1960 IO List & zip
     1961 IO List & zip
     1962 IO List & zip
     1963 IO List & zip
     1964 IO List & zip
     1965 IO List & zip
     1966 IO List & zip
     1967 IO List & zip
     1968 IO List & zip
     1969 IO List & zip
     1970 IO List & zip
     1971 IO List & zip
     1972 IO List & zip
     1973 IO List & zip
     1974 IO List & zip
     1975 IO List & zip
     1976 IO List & zip
     1977 IO List & zip
     1978 IO List & zip
     1979 IO List & zip
     1980 IO List & zip
     1981 IO List & zip
     1982 IO List & zip
     1983 IO List & zip
     1984 IO List & zip
     1985 IO List & zip
     1986 IO List & zip
     1987 IO List & zip
     1988 IO List & zip
     1989 IO List & zip
     1990 IO List & zip
     1991 IO List & zip
     1992 IO List & zip
     1993 IO List & zip
     1994 IO List & zip
     1995 IO List & zip
     1996 IO List & zip
     1997 IO List & zip
     1998 IO List & zip
     1999 IO List & zip
     2000 IO List & zip
     2001 IO List & zip
     2002 IO List & zip
     2003 IO List & zip
     2004 IO List & zip
     2005 IO List & zip
     2006 IO List & zip
     2007 IO List & zip
     2008 IO List & zip
     2009 IO List & zip
     2010 IO List & zip
     2011 IO List & zip
     2012 IO List & zip kml
    Southern Hemisphere
    Western North Pacific
 
   NMFC
   JTWC

Last updated: 25 Apr 2013

Individual Best Track File Name Breakdown (examples):
bio011985.txt
bsh011985.txt
bwp011985.txt
io_storm_notes_1985.txt
io_year_notes_1985.txt
1985s-bio-full.zip
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Best-track-Indian-Ocean-01-Storm-1985.Text-format
Best-track-Southern-Hemisphere-01-Storm-1985.Text-format
Best-track-Western-Pacific-01-Storm-1985.Text-format
Northern Indian Ocean Storm Notes
Northern Indian Ocean Yearly Notes
Zip file of all 1985 Northern Indian Ocean Best Tracks and
storm/year notes if exist

Indian Ocean Best Track Data Format
  BASIN,CY, YYYYMMDDHH,TECHNUM, TECH,TAU, LatN/S,LonE/W, VMAX,MSLP,
TY,RAD, WINDCODE,RAD1, RAD2,RAD3, RAD4,RADP, RRP,MRD, GUSTS,EYE,
SUBREGION,MAXSEAS, INITIALS,DIR, SPEED,STORMNAME, DEPTH,SEAS, SEASCODE,SEAS1, SEAS2,SEAS3, SEAS4

BASIN - basin, e.g. WP, IO, SH, CP, EP, AL
CY - annual cyclone number: 1 through 99
YYYYMMDDHH - Warning Date-Time-Group: 0000010100 through 9999123123. (note, 4 digit year)
TECHNUM - objective technique sorting number: 00 - 99
TECH - acronym for each objective technique or CARQ or WRNG, BEST for best track.
TAU - forecast period: -24 through 120 hours, 0 for best-track, negative taus used for CARQ and WRNG records.
LatN/S - Latitude (tenths of degrees) for the DTG: 0 through 900, N/S is the hemispheric index.
LonE/W - Longitude (tenths of degrees) for the DTG: 0 through 1800, E/W is the hemispheric index.
VMAX - Maximum sustained wind speed in knots: 0 through 300.
MSLP - Minimum sea level pressure, 1 through 1100 MB.
TY - Level of tc development:
TD - tropical depression,
TS - tropical storm,
TY - typhoon,
ST - super typhoon,
TC - tropical cyclone,
HU - hurricane,
SD - subtropical depression,
SS - subtropical storm,
EX - extratropical systems,
IN - inland,
DS - dissipating,
LO - low,
WV - tropical wave,
ET - extrapolated,
XX - unknown.

RAD - Wind intensity (kts) for the radii defined in this record: 35, 50, 65 or 100.
WINDCODE - Radius code:

AAA - full circle
NNS - north semicircle
NES - northeast semicircle
EES - east semicircle
SES - southeast semicircle
SSS - south semicircle
SWS - southwest semicircle
WWS - west semicircle
NWS - northwest semicircle
QQQ - quadrant (NNQ, NEQ, EEQ, SEQ, SSQ, SWQ, WWQ, NWQ)

RAD1 - If full circle, radius of specified wind intensity, If semicircle or quadrant, radius
of specified wind intensity of circle portion specified in radius code. 0 - 1200 nm.
RAD2 - If full circle this field not used, If semicicle, radius (nm) of specified wind intensity
for semicircle not specified in radius code, If quadrant, radius (nm) of specified wind intensity
for 2nd quadrant (counting clockwise from quadrant specified in radius code). 0 through 1200 nm.
RAD3 - If full circle or semicircle this field not used, If quadrant, radius (nm) of specified wind
intensity for 3rd quadrant (counting clockwise from quadrant specified in radius code). 0 through 1200 nm.
RAD4 - If full circle or semicircle this field not used, If quadrant, radius (nm) of specified wind
intensity for 4th quadrant (counting clockwise from quadrant specified in radius code). 0 through 1200 nm.
RADP - pressure in millibars of the last closed isobar, 900 - 1050 mb.
RRP - radius of the last closed isobar in nm, 0 - 9999 nm.
MRD - radius of max winds, 0 - 999 nm.
GUSTS - gusts, 0 through 995 kts.
EYE - eye diameter, 0 through 999 nm.
SUBREGION - subregion code: W, A, B, S, P, C, E, L.

A - Arabian Sea
B - Bay of Bengal
C - Central Pacific
E - Eastern Pacific
L - Atlantic
P - South Pacific (135E - 120W)
S - South IO (20E - 135E)
W - Western Pacific

MAXSEAS - max seas: 0 through 999 ft.
INITIALS - Forecaster's initials, used for tau 0 WRNG, up to 3 chars.
DIR - storm direction, 0 - 359 degrees.
SPEED - storm speed, 0 - 999 kts.
STORMNAME - literal storm name, NONAME or INVEST. TCcyx used pre-1999, where:

cy = Annual cyclone number 01 through 99
x = Subregion code: W, A, B, S, P, C, E, L.

A - Arabian Sea
B - Bay of Bengal
C - Central Pacific
E - Eastern Pacific
L - Atlantic
P - South Pacific (135E - 120W)
S - South IO (20E - 135E)
W - Western Pacific

DEPTH - system depth, D-deep, M-medium, S-shallow, X-unknown
SEAS - Wave height for radii defined in SEAS1-SEAS4, 0-99 ft.
SEASCODE - Radius code:

AAA - full circle
NNS - north semicircle
NES - northeast semicircle
EES - east semicircle
SES - southeast semicircle
SSS - south semicircle
SWS - southwest semicircle
WWS - west semicircle
NWS - northwest semicircle
QQQ - quadrant (NNQ, NEQ, EEQ, SEQ, SSQ, SWQ, WWQ, NWQ)
SEAS1 - first quadrant seas radius as defined by SEASCODE, 0 through 999 nm.
SEAS2 - second quadrant seas radius as defined by SEASCODE, 0 through 999 nm.
SEAS3 - third quadrant seas radius as defined by SEASCODE, 0 through 999 nm.
SEAS4 - fourth quadrant seas radius as defined by SEASCODE, 0 through 999 nm.

Fields currently used for best track records:
BASIN, CY, YYYYMMDDHH, , TECH, TAU, LatN/S, LonE/W, VMAX, MSLP, TY
TECH = BEST
TAU = 0

All fields are used for objective-aids history records (CARQ,WRNG,COMS):
TECHNUM = 01 - CARQ and COMS, 00 - WRNG
TECH = CARQ, WRNG, COMS
INITIALS for WRNG/OFCL record
Repeated for tau -24 through tau 0

Fields for objective-aids forecasts records:
BASIN, CY, YYYYMMDDHH, TECHNUM, TECH, TAU, LatN/S, LonE/W, VMAX, MSLP, TY, RAD, WINDCODE, RAD1, RAD2, RAD3, RAD4
Repeated for tau 0 through tau 120
Wind records merged in from existing r-decks will be assigned a TECH of CNTR. Wind records created during normal use of the combined abr-deck will be assigned the TECH corresponding to the center name as defined in $ATCFINC/atcfsite.nam.


This review is the result of a coordinated effort between Naval Research Lab, Monterey and JTWC.
Persons involved are Dr. J H. Chu, Mr. A. Levine, Mr. S. Daida, Capt. D. Schiber, Mr. E. Fukada, Mr. C. R. Sampson.