Dennis now a Category 2 hurricane...

In the past 24 hours, Dennis' sustained winds have increased by 30kts 
and the central pressure has dropped 23mb.  Now a CAT2 storm, it is 
heading toward Jamaica and as of this update is just 70 miles from it.  
At 15Z, Dennis was located at 18.0N 75.6W and tracking NW at 11kts.  
Intensity as measured by aircraft is 90kts and 968mb.  A Hurricane Watch 
is in effect for the Florida Keys and extreme western Cuba.  Hurricane 
Warnings are in place for southern Haiti, all of Jamaica, the Cayman 
Islands, and the remainder of Cuba.

The forecast track takes Dennis between Jamaica and eastern Cuba, then 
over western Cuba, into the Gulf of Mexico by late Friday night, then 
possibly making landfall late Sunday or early Monday on the northern 
Gulf coast.  The computer models and the official forecast have 
consistently shown the area around Mobile, AL to Pensacola, FL as the 
most likely target for landfall, but remember that a) forecast errors do 
exist and b) the storm will affect a much larger area than where the 
exact center of the eye passes over.  Intensity is of course also 
important, and all skilled models and forecasters expect that landfall 
will occur as a major hurricane... Category 3 or 4.  What this means to 
coastal residents in eastern LA, MS, AL, and the FL panhandle is that 
now is the time to begin preparing your house and yourself for evacuation.

Elsewhere, a very large and impressive tropical wave exited the African 
coast a couple days ago and continues to show signs of an organizing 
broad circulation.  There's a 1014mb Low embedded within the wave, and 
it's moving west at about 12kts.  Several computer models do favor 
development of this wave.  It would be TD5, or TS Emily if named 
eventually.

Please visit my tropical Atlantic headquarters.