A strong tropical wave exited the coast of Africa Friday, and is now a 1006 mb low pressure system with heavy thunderstorm activity about 200 miles south of the Cape Verde Islands. NHC is referring to this system as 90L. This morning's QuikSCAT satellite pass at 3:48am EDT found an elongated circulation centered near 12.5N 23W, with top winds of 30 mph. Satellite imagery at the NRL Monterey web site that most people use to track eastern Atlantic storms is not available this weekend. A substitute source of imagery is available at the main Navy weather web site. The thunderstorm activity surrounding 90L is currently not very expansive, thanks in part to relatively cool SSTs of 26-27C and high wind shear of 20 knots. However, the cloud pattern has gotten more organized this morning, with some spiral banding starting to occur. SSTs should increase above 27C by Tuesday, as 90L moves away from the African coast at 15-20 mph. Wind shear should drop to 10-20 knots, and I expect 90L will become a tropical depression on Monday or Tuesday.



What the computer models say
Watching the computer model runs for 90L is not for the faint of heart. All the major models except the NOGAPS develop the system into a tropical storm or hurricane that tracks westward over the Atlantic, reaching the lesser Antilles Islands as early as Thursday night, August 16. There are four possible scenarios to consider:

1) A strong trough of low pressure is forecast to move off the East Coast of the U.S. at that time, and this trough may deflect 90L northwards so that it misses the Lesser Antilles Islands, and then recurves harmlessly out to sea.

2) In keeping with the steering pattern we've observed since late July, the trough is expected to rapidly move onward, allowing a ridge of high pressure to build in. If the trough is not strong enough to recurve 90L out to sea, the storm will be forced to the west once more and eventually hit the East Coast of the U.S. This is the solution of last night's ECMWF model.

3) 90L will be far enough south and next weekend's trough will be weak enough that 90L will plow through the Caribbean, and not be deflected north of the Lesser Antilles Islands. The storm would eventually track into the Gulf of Mexico. This is the solution preferred by this morning's GFS model.

4) 90L will never develop, or will never become more than a weak tropical storm, due to unfavorable wind shear, dry air, or other factors. This is the solution of the NOGAPS model.

Of the four scenarios, I believe #2 or #3 are most likely to occur--90L will develop into a tropical storm or hurricane that will affect the Caribbean and/or U.S. East Coast. Residents throughout the Caribbean and U.S. should anticipate the possibility that 90L may become a hurricane--and possibly a major hurricane--that will not recurve. If you plan on being in the Lesser Antilles Islands Thursday August 16 - Sunday August 19, keep in mind there is a heightened risk of a tropical storm or hurricane during that period. Be prepared to adjust your travel plans.

This material transferred from weatherunderground.

Weatherman

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Dr. Scott
Internal Medicine
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AUC Forum Moderator

TD4 is now Tropical Storm Dean. On it present projected path it should pass through the Antilles on Saturday. Present projections take the storm over or just north of Dominica as a category 1 hurricane on Saturday. The storm is still a long ways out and there is some possibility that the storm will track further north than what is expected at this time. All schools between Saint Martin on the north and Saint Lucia on the south should monitor the storm from this point on. By Sunday the storm should be nearing Puerto Rico as a category 2 hurricane. The path of the storm may disrupt air transport to many if not most of the schools.

Weatherman

here's a the 5-day cone from the national hurricane center

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Posterior Fornix!

Me fail English? That's unpossible. - Ralph Wiggum

I need a rain coat and some storm surge protectors.

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Something that bothers you, just flush it off and wipe the remaining patiently. RS-Stanislas

looks like it's gonna be near dominca. i hope people at ross will be prepared

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Posterior Fornix!

Me fail English? That's unpossible. - Ralph Wiggum

They have brick buildings to handle such storm. They should be fine, maybe

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Something that bothers you, just flush it off and wipe the remaining patiently. RS-Stanislas

So exactly where is Ross located?

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Ross is in Dominica....or if this becomes a big storm was located in Dominica. Hopefully they, faculty, will have some sort of clue how to handle a category 2 hurricane and the disster it brings.

i hope ross won't be blown towards puerto rico.

__________________
Posterior Fornix!

Me fail English? That's unpossible. - Ralph Wiggum