Huntsville Airshow Thunderstorm

At approximately 2:05 PM CDT, a strong thunderstorm hit the Huntsville International Airport during the 2008 Huntsville Airshow. The Huntsville ASOS (Automated Surface Observing System) recorded a 48 mph gust from 300 degrees (NW) at that time. Approximately 17 minutes earlier, at 1:48 PM, the same storm produced a 33 mph wind gust at the Decatur airport in southern Limestone County. A thunderstorm becomes severe when it produces wind gusts of 58 mph or greater, or hail larger than 3/4 inch in diameter (generally the size of a penny).

The damage and injuries that occurred at the Huntsville Airshow were determined to originate from a non-severe microburst. Microbursts are downdrafts that occur from some thunderstorms, hit the ground, and spread out, producing strong gusty winds at the earth's surface. Microbursts are fairly frequent across the southeastern United States in the summertime, often occurring with very strong thunderstorms, but significant microbursts can occur even within weaker thunderstorms.

Here are some radar images from the Hytop, Alabama (KHTX) doppler radar just prior to the event (click the image to enlarge):