Wednesday, May 14, 2008

Mother's Day Severe Weather Outbreak - May 10th & 11th, 2008

Event Summary for Central Alabama - Surveys are still underway.

Severe weather developed late Saturday evening, May 10th, across Central Alabama and continued into the early morning hours on Mother's Day, May 11th. Damaging winds, large hail, tornadoes, continuous lightning and minor flooding were all produced by these thunderstorms.

A warm front moved very slowly northward through Central Alabama on May 10th. The atmosphere in the vicinity of the front and southward was extremely unstable. Additionally, moisture was pooling along and south of the front. On Saturday, warm air just above the surface, referred to as a cap, limited the strength and overall development of thunderstorms for much of the day. An upper level disturbance moved from west to east over Central Alabama late Saturday evening into early Sunday morning. This disturbance had several effects which aided the development of much stronger and more widespread thunderstorms. This disturbance eroded the cap, produced much stronger winds just above the surface, and pushed a cold front through the region. Therefore, the overall environment was characterized by high wind shear and moderate capes. This severe episode was highlighted in the Birmingham Hazardous Weather Outlook several days before the event.

Tornado Watches were in effect for portions of Central Alabama between 700 pm and 800 am May 10th into May11th.

Identified damage paths;

EF-1 Marion County Tornado
EF-1 Heflin Tornado - Cleburne County
EF-1 Cleburne County Tornado
Straight Line Wind Damage - Winston County
Preliminary Local Storm Reports

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