29 August 2010

Danielle weakens, Earl becomes 3rd hurricane, still no TD8...

Since my update on Friday morning, Danielle has recurved and weakened as forecast.  The hurricane made a sharp turn to the NE well before reaching Bermuda, and is now accelerating and heading toward the cold waters of the north central Atlantic.  At 15Z today, the intensity was 75kts and 976mb, and the heading was NE at 23kts.  As it comes under the influence of the mid-latitude environment of colder SSTs and strong westerly wind shear, it will begin its extra-tropical transition, and is forecast to become fully extra-tropical by late Monday into Tuesday.

Earl, on the other hand, has finally entered a more favorable environment for intensification, and at 15Z today was upgraded to the third hurricane of the season with winds of 65kts and a central pressure of 985mb (and forming an eye).  It's currently located about 225 miles east of Antigua and heading W at 15kts.  A side-effect of not intensifying sooner is that it was steered by lower-level winds rather than mid-level winds that steer stronger storms, and has moved quite a bit further west without much of a northward component.  This will bring the storm very close to the Leeward Islands and perhaps the eastern US seaboard.  There are Hurricane Warnings for the northern Leeward Islands and Hurricane Watches for Puerto Rico and the Virgin Islands.  The storm will affect these islands tonight into Monday as it likely intensifies into the second major hurricane of the season.  The islands with the highest risk of hurricane-force winds are the northeastern-most, such as Antigua, the Virgin Islands, St. Croix, St. Eustatius, St. Kitts, Nevis, and especially
Barbuda, Anguilla, St. Maarten, and St. Barthelemy.

As far as the track forecast is concerned, the majority of global and regional models do not indicate a US landfall for Earl, though it should be watched very closely because the latest consensus has the track halfway between Bermuda and the US coast, which is certainly with the 5-day margin of error.  The "extremities" of the coast should be particularly watchful... areas like Cape Hatteras and Boston and northward to Nova Scotia and Newfoundland.

The easterly wave that exited the African coast on the 25th has still not gotten organized enough to be classified as a Depression.  It's currently located at about 14N 39W and lacking persistent deep convection.  However, nearly all models are forecasting significant intensification within 2-3 days, and more of a WNW track than Danielle and Earl took.  Of the 3 storms, this "pre-Fiona" is the one with the highest US landfall risk.  It's far too early to say where it would be, but in the shorter term, the track is forecast to remain to the south of the others, increasing the likelihood that it will not recurve as far east as the others.  It's also quite likely to affect the same islands in the Caribbean that Earl is, so it will be a rough week for them (this encounter would be Wednesday-Thursday, just 3 days after Earl).

Please visit my tropical Atlantic headquarters.

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