Friday, August 25, 2006

Ernesto heads for the Gulf Coast

Jeff Masters

The latest 12Z (8am EDT) model runs are in, and they portray a conflicting picture of what may happen. Three of the four major global models--UKMET, GFS, and NOGAPS--dissipate or severely weaken the storm by Monday. The Canadian model, which has been the most aggressive in making Ernesto a hurricane in the Gulf of Mexico, now keeps the system a weak tropical storm all the way to landfall in the Florida Panhandle on Tuesday. The European Center model has a similar forecast. Oddly, the large upper-level trough of low pressure over the central Caribbean is forecast by these models to move west away from Ernesto, and an upper level high pressure system to build on top of the storm. This situation should act to lower the shear and aid in intensification, and that it what the official NHC forecast is calling for. It is unusual for the models to forecast a favorable shear environment, yet dissipate a storm, and serves to show the limitations of these models in making hurricane intensity forecasts. I have very little confidence in any of the Ernesto intensity forecasts--including the official NHC forecast of a hurricane in the Gulf of Mexico on Tuesday. High wind shear could still destroy this storm on Sunday. Ernesto should slowly intensify through Saturday, but beyond that, I have no idea. It's best to prepare for the worst, and hope for the best. All portions the U.S. coast from the Florida Keys to Brownsville, Texas are at risk from this storm.

Tropical Depression 05 regional imagery, 2006.08.25 at 1145Z. Centerpoint Latitude: 13:43:20N Longitude: 65:00:59W.

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