by Phil Hysell

The National Weather Service started storm-based warnings October 1st, 2007, for tornadoes, severe thunderstorms, flash floods and marine hazards that are more geographically specific for these short-duration weather events. Previously, such warnings were issued county wide.

"Weather doesn't follow geopolitical boundaries," said retired Air Force Brig. Gen. David L. Johnson, former director of the NOAA National Weather Service. "Storm-based warnings provide the public with more specific information about the location of severe weather and the direction it is expected to move. Seconds count during tornadoes and flash floods. We want to provide the public with the most accurate description of what's happening in their neighborhood. We also want to avoid warning non-threatened portions of the county."

When issuing a warning, the NOAA National Weather Service will specify areas within a county and refer to commonly known landmarks such as highways or rivers.

"This is a fundamental change in our warning procedures and a major enhancement in our service capability," said Johnson. "Storm-based warnings will drastically improve graphical displays and empower the private sector to easily distribute the information through Web-enabled PDAs, cell phone alerts, pagers and other technologies. Communicating severe weather threats in this way is imperative in today's digital world."

Dave Wert, Meteorologist In Charge at the National Weather Service in Blacksburg says with the new system, a red box or polygon will show exactly where the threat really lies.
"The false alarms will go down because less area will be warned that doesn't need to be warned. It will be far better in both time and space, very much more accurate."


Polygon Warning Example