Weatherdem's Weblog

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Atlantic Tropical Weather Update 8/12/09

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Tropical Depression Two continues to move steadily westward across the Atlantic basin.  It’s vitals as of this morning:

Center near 14.3°N, 33.8°W; moving W @ 12mph; maximum sustained winds of 35mph; minimum pressure ~1006mb.

There has been a small change in the official forecast track since yesterday: instead of curving to the northwest in the next couple of days, T.D. 2 is now expected to stay near 15°N a little longer.  This is in response to a tropical ridge that is now forecasted to remain in place and strengthen to T.D. 2’s north.  I’d like to note that the UKMET and GFS models keep T.D. 2 furthest south out of all the models.  It will be instructive to see how their solutions verify in the extended forecast period (3-5 days out).

As before, two factors are limiting T.D. 2’s potential development.  SSTs remain a little low – around 27-28°C.  Dry Saharan air remains to T.D. 2’s north.  To attain Tropical Storm strength, T.D. 2 needs to tap into a larger area of warm, moist air.  The dry, stable, desert air on the north side of the storm cuts off the necessary moist air.  So until that air is modified by passing over the ocean or a different airmass is brought near T.D. 2, there will be no quick development of the storm.  T.D. 2 should slowly gather some further organization as a dominant center establishes itself nearer the convective towers currently on its western periphery.  At this time, I doubt T.D. 2 will strengthen beyond Tropical Storm force.

The disturbances near the Windward Islands have fallen apart.  A very small region of thunderstorms remains, and it’s too close to the South American coast to get very organized.

The vigorous tropical wave coming off the west coast of Africa remains in good shape.  It currently has storms over a wide region between the African coast and the Cape Verdes Islands.  This tropical wave has been given a 30-50% chance of developing into a Tropical Depression in the next 48 hours.  This disturbance looks like its embedded in a more favorable environment than T.D. 2.  Mid- and high-level air is much more moist than the air to T.D. 2’s north.  That could, of course, change in the next few days.


One thought on “Atlantic Tropical Weather Update 8/12/09

  1. Pingback: Atlantic Tropical Weather Update 8/13/09 « Weatherdem’s Weblog

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