11 P.M. advisory just came out, and it's official; Dennis is now a Category 4 with sustained winds of 135 mph and a minimum pressure of 950 millibars. The NHC indicates that further strengthening is possible before Dennis crashes into the south central coast of Cuba and makes a beeline for Havana. They also indicate Dennis dropping to 100 knots after he smashes through Cuba, then restrengthening to 110 knots before landfall along the Gulf Coast, most likely between Mobile, AL and Apalachicola, FL.
The latest NHC guidance has shifted back to the west slightly, so it looks grim for Pensacola at the moment.
They still may be underplaying the restrengthing a little bit, but that can be expected for wind speed predictions this far out. According to the discussion, the guidance models have shifted back westward, and Gulfport and New Orleans are back in the potential target area. From the 11 P.M EDT NHC Discussion: THE INTENSITY FORECAST IS PROBLEMATIC. IN THE SHORT TERM...DENNIS
COULD CONTINUE TO STRENGTHEN UNTIL THE CORE ENCOUNTERS CENTRAL
CUBA...AND THIS IS REFLECTED IN THE INTENSITY FORECAST. AFTER
THAT...SEVERAL FACTORS COME INTO PLAY. THESE INCLUDE...WILL THE
CURRENTLY TIGHTLY WOUND CORE OF DENNIS SURVIVE PASSAGE ACROSS
LAND...WHAT CONCENTRIC EYEWALL CYCLES MAY OCCUR...AND HOW MUCH
ENERGY IS AVAILABLE IN THE WARM...BUT THIN...SURFACE LAYER OF THE
GULF OF MEXICO. THE SHIPS MODEL SUGGEST THAT THE OCEANIC HEAT
CONTENT WILL DECREASE AS DENNIS MOVES NORTHWARD...CAUSING THE STORM
TO WEAKEN. ON THE OTHER HAND...THE GFDL AND GFDN BOTH CALL FOR
SIGNIFICANT INTENSIFICATION OVER THE GULF. THE INTENSITY FORECAST
WILL COMPROMISE BETWEEN THESE EXTREMES.
I'm not even going to try to guess what intensity will be at or where he will be heading the next 36 hours. It is completley up in the air right now and it probably will not be apparent where he is headed until Saturday. I have a bad feeling that Dennis may pull a Charley and make a sudden turn as he approaches the coast. Like I said, it is too problematic at this point to even attempt to guess where this monster is heading and how strong it will be.
Being a Cat 4 and all, Cuba is probably going to be devastated by Dennis, especially the central part of that island. Pray for them tonight.

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