Monday, November 17, 2014   |   Critical Weather

Radar View of the Blountstown, Florida Tornado Event

A brief but strong tornado hit the town of Blountstown, Florida around 4:20am CST. Radar data from the event shows exactly where the tornado touched down this morning.


At 3:56 a.m., reflectivity data from EVX shows a supercell of thunderstorms, with a hook echo and Baron Shear Markers to the southwest of the city. Storm arrows are pointing in the exact direction of Blountstown, Florida, roughly 25-30 minutes before the tornado would touch down.


Velocity data at the same time shows a relatively broad circulation with the storm.


10 minutes later at 4:05 a.m., the storm now has a well- defined hook in reflectivity data as it is quickly approaching the town.


Velocity data at 4:05 a.m. shows the circulation becoming stronger. The couplet is also becoming tighter, indicating the storm is intensifying.


By 4:18 a.m. the storm is moving through the town of Blountstown. Reflectivity data shows a large hook echo with the storm as it moves through the south part of town.


Velocity data at the same time now shows a strong circulation with the storm. This indicates hat a tornado is likely occurring within the storm.


Resampled RHO (Correlation Coefficient) at 4:18 a.m. shows an area of low values (blue area) in the exact location of the hook echo in reflectivity, and the strong circulation in velocity data. This low RHO values tell us that radar returns are very non-uniform. This expected when the radar is detecting possible debris that has been lofted into the air by a tornado.


Resampled RHO at this same time shows a large area of very low values, indicating likely tornado debris being detected by radar.


At this time, the Baron-derived TDS Swath shows locations likely affected by the tornado. The TDS Swath product indicates an area of tornado debris over Blountstown, Florida.

blountstown_434_shear rate_swath

The Baron-derived Shear Swath shows us the path with the highest amount of storm-associated shear; this path went directly over Blountstown, Florida.


On the next scan at 4:27 a.m., the storm has already passed through the town, and reflectivity data shows the storm has weakened. There is now no hook echo or donut hole in the reflectivity. At this time the tornado has likely lifted off the ground.

Baron-derived shear markers/SCITs were present with the storm over 30 minutes before the tornado touched down, giving forecasters and the public plenty of lead time for the tornado. Additional Baron-derived products, including Resampled RHO, TDS Swath and Shear Rate also showed exactly where the tornado occurred this morning.