Tropical Depression TWENTY-FOUR

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TROPICAL DEPRESSION TWENTY-FOUR DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SAT OCT 15 2005
 
THE CYCLONE IS STILL IN THE FORMATIVE STAGES AND DOES NOT YET HAVE
VERY MUCH DEEP CONVECTION NEAR THE CIRCULATION CENTER... BUT OUTER
BANDING FEATURES SEEM TO BE GRADUALLY CONSOLIDATING.  THE CYCLONIC
CIRCULATION ENVELOPE IS WELL-ESTABLISHED... AS IS UPPER LEVEL
ANTICYCLONIC OUTFLOW.  A 23Z QUIKSCAT OVERPASS HAD SOME 30-35 KT
VECTORS THAT ARE PROBABLY RAIN CONTAMINATED... SO THE ADVISORY
INTENSITY REMAINS 25 KT.
 
THE DEPRESSION HAS BEEN DRIFTING SOUTHWESTWARD FOR THE PAST FEW
HOURS...AT ABOUT 225/3. THE WEAK STEERING RESULTS FROM THE
DEPRESSION BEING STUCK BETWEEN MID-LEVEL RIDGES CENTERED OVER THE
WESTERN GULF OF MEXICO AND THE CENTRAL TROPICAL ATLANTIC OCEAN.
THIS RELATIVE WEAKNESS IN THE RIDGING IS ASSOCIATED WITH A
MIDLATITUDE LOW PRESSURE SYSTEM NEAR THE NEW ENGLAND STATES. THE
FLOW AROUND THE GULF RIDGE APPEARS TO HAVE A SLIGHTLY GREATER
INFLUENCE FOR NOW... AND THE DYNAMICAL MODELS FORECAST THE GULF
RIDGE TO REMAIN IN PLACE FOR THE NEXT COUPLE OF DAYS. THEREAFTER...
THE MODELS SHOW THE GULF RIDGE MIGRATING WESTWARD... LEAVING A
GROWING WEAKNESS OVER THE EASTERN GULF AND ALLOWING THE
WESTWARD-BUILDING RIDGE OVER THE ATLANTIC TO BEGIN PUSHING THE
TROPICAL CYCLONE NORTHWARD. SINCE THIS PATTERN CHANGE IS FORECAST
TO OCCUR SO GRADUALLY... NONE OF THE GLOBAL MODELS... EXCEPT FOR
THE CANADIAN... FORECAST THE TROPICAL CYCLONE TO LEAVE THE WESTERN
CARIBBEAN SEA WITHIN THE NEXT FIVE DAYS. THE OFFICIAL FORECAST IS
SOUTH OF THE PREVIOUS ADVISORY FOR THE FIRST COUPLE OF DAYS TO
ADJUST FOR THE INITIAL MOTION... THEN BACK ON TRACK THEREAFTER...
AND CLOSE TO A BLEND OF THE GFS AND GFDL.
 
ATMOSPHERIC AND OCEANIC CONDITIONS APPEAR CONDUCIVE FOR
STRENGTHENING. EVEN THOUGH THE FORWARD MOTION WILL BE SLOW... THE
LARGE OCEANIC HEAT CONTENT SHOULD CONTINUE TO SUPPLY FUEL FOR
INTENSIFICATION WHILE VERTICAL SHEAR REMAINS WEAK BENEATH A LARGE
UPPER-LEVEL ANTICYCLONE. THE COUPLED GFDL SYSTEM FORECASTS A
HURRICANE IN ABOUT 36 HOURS WITH CONTINUED STRENGTHENING TO GREATER
THAN 90 KT IN LESS THAN 72 HOURS... WHILE SHIPS SHOWS STEADY BUT
MORE CONSERVATIVE STRENGTHENING. THE OFFICIAL FORECAST IS IN
BETWEEN AND IS SIMILAR TO THE PREVIOUS ADVISORY.
 
FORECASTER KNABB
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/0300Z 17.0N  79.0W    25 KT
 12HR VT     16/1200Z 16.8N  79.5W    35 KT
 24HR VT     17/0000Z 16.6N  80.0W    45 KT
 36HR VT     17/1200Z 16.6N  80.4W    55 KT
 48HR VT     18/0000Z 16.8N  80.8W    65 KT
 72HR VT     19/0000Z 17.5N  81.5W    75 KT
 96HR VT     20/0000Z 18.5N  82.5W    85 KT
120HR VT     21/0000Z 20.5N  83.0W    85 KT
 
 
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