North Texas Graphical Severe Weather Warnings Explained
Click Here For The Graphical Warnings Page

The graphical severe weather warnings represent a collaborative effort between the National Weather Service Fort Worth, TX, the NWS Southern Region Headquarters, and the North Central Texas Council of Governments. The graphical warnings are generated whenever a Severe Thunderstorm, Tornado, or Flash Flood Warning is issued by the Fort Worth NWS office. The graphical severe weather warning uses radar reflectivity data from the Fort Worth WSR-88D Doppler Weather Radar and overlays the area at risk for severe weather as drawn by the warning forecaster during the warning preparation phase. This area at risk is known as a "warning polygon", and appears as a lat/lon string at the bottom of every NWS short-fuse severe weather warning.

Using the "warning polygon" area, a demographic database at the North Central Texas Council of Governments is queried to determine characteristics of the population at risk. These characteristics include total population, population by sex and age within each city or town in the path, the percentage living in single family homes, multi-family dwellings, and manufactured homes. Additionally, the percentage of the population that, by their own responses to the 2000 Census, do or do not speak English is determined, and the percentage living in urban and rural locations. Finally, the percentage of the population in the path of the storm that (again, based on 2000 Census responses) did not live in Texas in 1995 is determined. This is thought to provide some measure of the relative number of people who are new to the area and may not be familiar with Texas weather.

This effort introduces Geographic Information System (GIS) technology to the NWS Fort Worth warning process. This tool allows weather data at the NWS to directly integrate with high resolution geographic data created and maintained by the local and regional governments of North Central Texas. 

You can view an example by clicking here.

We welcome feedback on this experimental service, and ask you to send your comments to SR-FWD.webmaster@noaa.gov.