Concerns over whether Earl may directly impact the Leewards, Virgin Islands, and potentially Puerto Rico may have slightly increased this a.m. Latest discussion indicating somewhat divergent modeling between 48-72 hours and a slight southward shift to Earl's forecast track. As is often the case, any one or several nuances regarding Earl's near term motion and development would certainly have the potential impact that could easily result in a 50-150 mile later course adjustment. Though perhaps the biggest player in the "grand scheme", may actually be Hurricane Danielle. A persistent W. Atlantic trough will be reinforced by Danielle's presence, and yet with the much anticipated 594mb mid level high forecast to exert its presence over the mid-Atlantic seaboard by late weekend, the big question is to what extent does this ridging extend to ( or become bridged to ) the east.
The timing in which Danielle finally pulls more poleward and begins to get caught by a dropping shortwave and finally accelerates her Northeastward, might have the greatest impact on whether troughing conditions begin to influence Earl to re-curve well east of the Lessor Antilles - or for ridging to build in thus forcing Earl to trek West to WNW'ward. Ultimately, such ramifications of a direct impact to the Islands would indicate a potentially strengthening storm caught under a strong mid-Atlantic ridge who's mid level steering would seem to indicate a very real threat to the S.E. U.S. Even if this pattern is only transient, the timing would seem to indicate Earl as perhaps a greater landfall risk, than the invest to its east. Should Danielle remain on forecast, or even linger (before being jettisoned N.E.'ward), or perhaps should Earl slightly accelerate in its own forward motion, such would more than likely insure that Danielle's mid latitude weakness would enhance Earl to shift more Northwestward prior to direct impact to the Islands.
On the other hand, Tropical Storm Earl could remain weaker in the near term or possibly progress Westward somewhat slower than anticipated. Perhaps Danielle makes a somewhat quicker departure to the north and east, thus causing any current "weakness" to eventually fill. Though not likely, one or several of these components could cause a significantly increased risk of a major hurricane landfall event, to both the Lesser Antilles AND the U.S.
(Post moved to the appropriate Forum for long range predictions.)
Edited by Ed Dunham (Fri Aug 27 2010 06:47 PM)