Extended Best Track Data, source: http://rammb.cira.colostate.edu/research/tropical_cyclones/tc_extended_best_track_dataset/
Description of the Extended Best Track File (ebtrk_atlc.txt) (ebtrk_epac.txt) Version 2.03 Aug 06, 2015
Based on NHC Atlantic HURDAT Downloaded Aug, 15 2012 East Pac HURDAT Downloaded Aug, 15 2012
2012 cases from ATCF b-decks 2013 cases from ATCF b-decks 2014 AL cases from ATCF b-decks
Currently Supported by NESDIS/RAMMB and CIRA
Previous project contributors
Mark DeMaria NESDIS/StAR/Regional and Mesoscale Meteorology Branch CIRA/Colorado State University West Laporte Avenue Fort Collins, CO 80523
with contributions from Jeremy Pennington and Krislyn Williams formerly of the Tropical Prediction Center/National Hurricane Center 11691 SW 17th Street Miami, FL 33165
The National Hurricane Center (NHC) maintains a climatology of all Atlantic tropical cyclones since 1851. For each storm, the data file contains estimates of the latitude, longitude, 1-minute maximum sustained surface winds, minimum sea-level pressure, and an indicator of whether the system was purely tropical, subtropical or extra-tropical at 6-hour intervals. This data set is sometimes referred to as HURDAT. One limitation of the HURDAT file is that it does not contain any information about the storm size. As part of the operational forecasting procedure, NHC routinely estimates the radii of 34, 50 and 64 kt winds, the radius and pressure of the outermost closed isobar, the radius of maximum wind, and the diameter of the storm eye, if one exists. Under original support from the Risk Prediction Initiative, this operational data for the period 1988-1997 was digitized and combined with the information from the HURDAT file. Although the RPI project was completed in 1999, the file is updated by NESDIS/ORA for development of satellite algorithms, using data supplied by NHC personnel.
Version 1.0 - Feb 1998 - All variables for 1990-1997 Version 1.1 - Apr 1998 - All variables for 1988-1997 except max wind radii for 88-89 Version 1.2 - Feb 1999 - All variables for 1988-1997 Version 1.3 - Apr 2000 - All variables for 1988-1999 Version 1.4 - Mar 2001 - All variables for 1988-2000 Version 1.5 - Apr 2003 - All variables for 1988-2002, updated NHC best track file 1988-2002 used, which includes category 5 upgrade of Andrew 1992 Version 1.6 - Feb 2004 - All variables for 1988-2003 Version 1.7 - Mar 2007 - All variables for 1988-2006 All changes to HURDAT as of March 2007 included. 34, 50 and 64 kt wind radii since 2004 are from NHC best track. NHC began creating best track wind radii in 2004; radii from 1988-2003 are still the operational radii. An east Pacific extended best track was added in version 1.7 called ebtrk17_epac.txt. It includes the years 2001-2006. version 1.8 - Feb 2008 Cases from 2007 season added. version 1.9 - May 2009 Cases from 2008 season added. Some missing data from tropical storm Zeta (2005-06) added Storm numbers from 1997 modified for consistency with NHC numbering convention Minor changes to HURDAT since 2008 incorporated version 1.10 - Nov 2010 Cases from 2009 season added. version 1.11 - Jun 2011 Cases from 2010 season added. version 2.00 - Aug 2012 Cases from 2011 season added. New field added to end of record showing distance to nearest major landmass (km). version 2.01 - Feb 2013 Cases from 2012 season added. version 2.02 - Feb 2014 Cases from 2013 season added. version 2.03 - Aug 2015 AL Cases from 2014 season added
Note: If you need to refer to the extended best track file in a publication, a very brief description can be found in the following paper:
Demuth, J., M. DeMaria, and J.A. Knaff, 2006: Improvement of advanced microwave sounder unit tropical cyclone intensity and size estimation algorithms. J. Appl. Meteor., 45, 1573-1581.
The radius and pressure of the outer closed isobar and the radius of maximum wind were not routinely estimated as part of the NHC operational forecast procedure prior to 1990. The outer closed isobars and pressures from 1988-89 that were added in version 1.1 were estimated from the tropical surface analyses which were prepared operationally by NHC. These surface analyses were extracted from the NHC microfilm archive and the radius and pressure were estimated manually by J. Pennington. The radius of maximum winds for 1988-89 that were added in version 1.2 were obtained from the vortex messages of aircraft reconnaissance missions. These values were smoothed in time (the nearest three observations were averaged) to give the estimates included in the extended best track data file. The wind radii for this period (1988-89) are only included for cases where aircraft data was available.
All of the parameters not available in the HURDAT file were estimated
from operational data sources, including ship and other surface reports,
aircraft reconnaissance data and satellite imagery. At present, there are
no error estimates for these variables. Generally speaking, these
parameters are more reliable west of 55 longitude, where aircraft
reconnaissance data is usually available. Also, because the data is
operational, there is no guarantee that all of the parameters are
consistent. For example, the radius of 50 kt winds might be smaller
than the radius of 64 kt winds, even though this arrangement is not
physically possible. Note that in version 1.7 and higher the wind radii
are from the NHC best track.
The extended best track file uses a simple ASCII format. There is one line of data for each date and time period (00, 06, 12 or 18 UTC) of each storm (see sample line listed below). The information is given in the following order: Storm identification number, storm name, month, day, time, year, latitude (deg N), longitude (deg W), maximum wind speed (kt), minimum central pressure (hPa), radius of maximum wind speed (nm), eye diameter (nm), pressure of the outer closed isobar (hPa), radius of the outer closed isobar (nm), radii (nm) of 34 kt wind to the NE, SE, SW and NW of the storm center, radii (nm) of 50 kt wind to the NE, SE, SW and NW, radii (nm) of 64 kt wind to the NE, SE, SW, NW, and a storm type code. This code is either * for a tropical system (tropical depression, tropical storm, or hurricane), W for tropical wave, D for a tropical disturbance, S for a subtropical storm, E for an extra-tropical storm, or L for remnant low. The last record is the distance to the nearest major landmass (km), where the island of Trinidad is the smallest area considered to be land. Negative values indicate the storm center is over land.
Each item above is separated by a space in the file except the following: The month, day, and time are listed as one 6-digit number following the storm name. For example, 06 UTC on July 10 would be listed as 071006. Also the 34, 50, and 64-knot wind radii are separated from one another, but the radii for the four directions (NE, SE, SW, NW) are grouped together (12 characters). If any of these radii are less than 100 nm, a space will occur within the grouping. Thus, a wind radii group 125 25100100 indicates that winds at the given speed occur 125 nm to the NE, 25 nm to the SE, 100 nm to the SW, and 100 nm to the NW of the storm center. The following is a complete line of text from the extended best track file:
AL0290 ARTHUR 072518 1990 13.1 63.7 60 995 30 -99 1012 180 60 60 60 60 30 0 0 30 0 0 0 0 * 267.
A -99 in any parameter is a default value that means no estimate was available.