NWS Huntsville Revising Winter Weather Criteria

Because our mission is to protect life and property from significant weather, we continually review and adjust our weather products and services in order to improve service to our customers.

Beginning December 15, 2007, the National Weather Service in Huntsville will utilize adjusted criteria that will trigger the issuance of winter weather advisories and warnings across northern Alabama and southern middle Tennessee. Below is a list of changes with the new criteria and their associated weather products:

Winter Weather Advisory:
Snow and/or sleet accumulation of 1 to 2 inches in less than 24 hours. This product will also be issued for events with less than 1 inch of snow and/or sleet where significant travel impacts are expected, such as when ground temperatures are below 32ºF degrees prior to snowfall.

Ice Storm Warning:
Ice accumulation of greater than or equal to 0.25 inches in less than 24 hours.

A note about the effect of varying terrain across northeast Alabama and portions of southern middle Tennessee:
Long-fused watches/warnings and advisories are currently issued by county. To account for the complex terrain across portions of our forecast areas, particularly northeast Alabama and southern middle Tennessee, determination of the winter weather products will lean toward the "worst case scenario", or typically the "high end" snow or ice accumulation for a county or zone.

For example (in counties/zones with complex terrain), if areas above 1200 feet are forecast to receive 3-4 inches of snow while areas below 1200 feet receive 1-2 inches, a winter storm warning will be issued. Specific wording in the product will mention the expected accumulations at different elevations and locations.

Questions or comments can be directed to our warning coordination meteorologist (WCM) Tim Troutman, who can be reached at (256) 890-8503, extension 223.