nctcog logo
weather label

Graphical Warning Project

Severe Storm Arlington 1996

The graphical severe weather warnings project (GWARN) represents a collaborative effort between the National Weather Service Fort Worth, TX, the National Weather Service Southern Region Headquarters, and the North Central Texas Council of Governments.

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" or "storm-based warning".

graphical 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.

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.

 North Central Texas Council of Governments | 616 Six Flags Drive P.O. Box 5888 Arlington, TX 76005-5888
 Main Operator: (817) 640-3300 | Fax: (817) 640-7806