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Tropical Storm Watch posted for Western Florida

Tropical Storm Alberto is definitely starting to look like something that we would see in the Northeast Atlantic. The convection is completely displaced from the center of circulation, and that is where the tropical storm forces are located right now. Radar echoes from both Key West, Tampa, and La Bajada, Cuba are indicating large curved bands of rain and thunderstorm. Such curved bans are a sure sign of a circulation. However, this center of circulation is nowhere near those bands.

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Southeast U.S. radar

Inrafred satellite imagery is not showing a lot of active convection near the center, however, there are large rain bands to the east of the center. By far, most of the storm's convection is on the east side where the tropical storm force winds keep being reported.

The visible satellite image is clearly showing that well defined circulation in the central Gulf of Mexico. Note the curved low level clouds wrapping into the center of circulation. However, this also shows how far from the center the large bands really are. Also note the lack of any cloudiness in the western Gulf of Mexico.

It is going to be very hard for more convection to fire up near the center of circulation. A quick look at the water vapor imagery shows the large mass of dry air over the Western Gulf of Mexico. At this rate Alberto may not survive the trip to Florida.

Cuba and the Florida Keys have been getting a lot of rain as a result of this storm. Radar estimates from Key West indicate up to a foot of rain has fallen across Cuba from the depression. However, the estimates are likely conservative in many localities where the terrain enhances rainfall.

The computer models are clearly locking onto Northern Florida for a future landfall if Alberto is able to survive that long. Considering this consistency in the track, it is surprising to note that Alberto thus far has been holding on the left side of the expected track. If this trend continues it would keep the center of the storm under more hostile conditions and bring it toward the northern Gulf Coast. Recent trends in the models and storm track have led to a slow down in the motion of the storm.

After crossing Florida, the models call for the system to continue to track of the East Coast. However, it should transition to an extratropical system along the way. I don't expect Alberto to survive much beyond Florida, if he even gets that far.

Intensity forecasts are another matter completely. How lucky do you feel? About 2/3 of the models are calling for gradual intensification, while the other third are calling for no further development.

As for forecast wind speeds, once again the models are split down the same lines. The consensus seems to be to keep the system a weak tropical storm. While last night the GFDL was calling for Alberto to reach hurricane strength, it has since backed off that forecast. Only weak, if any, strengthening is likely.


Posted by Bryan Woods | Permalink