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National Warning GIS Shapefiles

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Warning Shapefiles Now Available As Single "ZIP"ped File


The National Weather Service produces short-term warnings to protect lives and property. Four types of warnings (Tornado, Severe Thunderstorm, Flash Flood, and Special Marine) include polygon information at the bottom of the warning, highlighting the primary threat area for the warning. Data from these warnings are collected and databased into a real-time set of GIS shapefiles. These files can be downloaded from this website in order to be used real-time in other Geographic Information Systems applications.

How to Access and Use These Files

The most convenient method to access these files is to download the single zip file that contains all the shapefiles for all four warning types (plus one for watches). Otherwise you can use an automated method such as "WGET" or a batch program that either gets all the files in and saves these files to the local directory that is used to store other shapefiles. These can then be easily added to your GIS application. If you're only interested in one type of warning, for example the Special Marine Warnings, then you will want to download the four files: SMW.SHP, SMW.DBF, SMW.SHX, and SMW.PRJ. The files can also be accessed manually by individually saving each file (Right-click on the links below and select "Save Link As").

SVR.SHP SVR.DBF SVR.SHX SVR.PRJ  (Severe Thunderstorm Warnings)
FFW.SHP FFW.DBF FFW.SHX FFW.PRJ  (Flash Flood Warnings)
SMW.SHP SMW.DBF SMW.SHX SMW.PRJ  (Special Marine Warnings)


Each ESRI-format shapefile consists of three files: (1) a file describing the shape of the polygon (*.SHP), (2) a file describing the data attributes of the data (*.DBF), and (3) an index file relating the other two files (*.SHX). In addition, a fourth file (*.PRJ) is provided in order to give proper projection information to align correctly with other geodata files. The files are organized by warning type. TOR = Tornado Warnings, SVR = Severe Thunderstorm Warnings, FFW = Flash Flood Warnings, and SMW = Special Marine Warnings. Therefore, in order to be able to use the real-time Tornado Warning Shapefile, you will need to download the four files: TOR.SHP, TOR.DBF, TOR.SHX, and TOR.PRJ. This same naming structure applies to the other three warning types as well.


The warning shapefiles are updated each minute, 24 hours a day, 7 days a week.


The underlying data that creates the shapefiles is purged each minute, looking for expired warnings.


Data attributes include extracted Valid Time Event Code (VTEC) information for all TOR, SVR, and SMW warnings. VTEC includes some vital easily-parsed information such as whether a warning is a test or not and what the valid start and expiration times are for the warnings. FFW's do not provide VTEC information at this time. All VTEC fields are included as part of the data attributes in the *.DBF files.

DBF Format

Field Name Description
1 ID Identification Number (Internal Use Only)
2 Issue Issue Date/Time (Format: MMDDHHMM in UTC/Z)
3 Expire Expiration Date/Time (Format: MMDDHHMM in UTC/Z)
3 ETN VTEC Event Tracking Number (see VTEC documentation for more info)
4 Status VTEC Code (normally = "O" for Operational)
5 Office VTEC 3-Letter Code Designating Issuing NWS Office
6 Action VTEC Code (normally = NEW for new warning)
7 Phenom VTEC Code for Phenomenon (MA=marine, TO=tornado, SV=severe thunderstorm, FA=flash flood)
8 Signif VTEC Code for Significance (W=warning)
9 Area Experimental Value for Area of Polygon (NOT operational yet!)

For More Info

For more information please refer to a Powerpoint presentation. If you have further questions feel free to contact Ken Waters.

National Weather Service
Pacific Region Headquarters
Geographic Information Systems Resources
737 Bishop St No 2200
Honolulu, HI 96813
Page last modified: Thursday, May 26, 2005
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