Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 2:40 PM GMT on March 15, 2008
A violent thunderstorm roared through downtown Atlanta at 9:40 pm Friday night, bringing tornado-force winds that injured 27 people and caused millions in damage. It is uncertain whether the wind damage was due to a tornado or a strong thunderstorm microburst. If it was a tornado, it was the only one for the day, since the Storm Prediction Center did not receive any other reports for tornadoes Friday. However, 96 reports of hail and 23 reports of damaging wind were received. Examination of the radar reflectivity loop shows the classic hook echo commonly accompanying tornadoes was present in the storm before and after it hit Atlanta, but not while it was over the city. The Doppler velocity loop shows that there was rotation associated with the thunderstorm that hit the city, and this rotation increased as the thunderstorm moved over the city. It is certainly possible that this thunderstorm spawned a tornado.
Figure 1. Radar reflectivity image of the March, 14, 2008 Atlanta, Georgia thunderstorm. No "hook" echo is evident in the image as the storm swept through Atlanta.
Figure 2. Doppler winds image of the March 14, 2008, Atlanta, Georgia thunderstorm. Note the region just northwest of the city showing blues and reds right next to each other, denoting strong winds moving both towards and away from the radar in a tight circulation. This is the signature associated with a mesocyclone--a rotating thunderstorm that commonly spawns tornadoes.
Severe weather is not done with the region yet--the Storm Prediction Center has placed northern Georgia and much of South Carolina under their "Moderate Risk" category for severe weather today, one level below the their highest level of risk. The Weather Underground Severe Weather page and Tornado page are good places to go to follow today's severe weather.
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