Tropical Depression TWENTY-FOUR

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TROPICAL DEPRESSION TWENTY-FOUR DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT SUN OCT 16 2005
 
THERE HAVE BEEN NO DRAMATIC CHANGES TO THE ORGANIZATION OF THE
DEPRESSION THIS MORNING...ALTHOUGH THERE IS MORE DEEP CONVECTION
NEAR THE CENTER WITH HINTS OF A LITTLE MORE BANDING.  THE LATEST
DVORAK CLASSIFICATIONS FROM TAFB AND SAB WERE UNCHANGED...AT
T2.5/35 KT...BUT AS NOTED IN THE PREVIOUS DISCUSSION...WITH SUCH A
BROAD WIND FIELD THE WINDS ARE PROBABLY STILL LAGGING THE SATELLITE
SIGNATURE.  AN AIR FORCE RECONNAISSANCE AIRCRAFT WILL BE REACHING
THE DEPRESSION EARLY THIS AFTERNOON TO BETTER ASSESS THE STRENGTH
OF THE CYCLONE.  THE UPPER-LEVEL FLOW PATTERN REMAINS EXTREMELY
FAVORABLE FOR DEVELOPMENT...WITH LOW SHEAR AND GOOD ANTICYCLONIC
OUTFLOW...AND THERE IS A DEEP SUPPLY OF WARM WATER IN THE NORTHWEST
CARIBBEAN.  THE RAPID INSTENSIFICATION COMPONENT OF THE SHIPS MODEL
IS INCREASINGLY SUGGESTING THE LIKELIHOOD OF RAPID DEVELOPMENT...
BUT A BETTER DEFINED INNER CORE STRUCTURE NEEDS TO FORM FIRST.  THE
GFDL MODEL BRINGS THE DEPRESSION TO MAJOR HURRICANE STATUS WITHIN
THREE DAYS...AND THE LARGE SCALE FACTORS ARE CERTAINLY IN PLACE TO
ALLOW THIS TO HAPPEN.  THE OFFICIAL FORECAST IS CLOSER TO THE SHIPS
MODEL EARLY IN THE FORECAST PERIOD BUT FAVORS THE GFDL LATER ON.

THE DEPRESSION APPEARS TO HAVE MOVED LITTLE OVER THE PAST SEVERAL
HOURS...AND PERHAPS MAY HAVE DRIFTED A LITTLE NORTHEAST OF THE
ADVISORY POSITION.  THIS TOO...WILL BE BETTER ASSESSED WHEN THE
RECONNAISSANCE AIRCRAFT ARRIVES.  THE SYNOPTIC REASONING OF THE
FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY.  THE CYCLONE IS
CAUGHT BETWEEN TWO MID-LEVEL HIGH PRESSURE CENTERS...WITH THE MORE
DOMINANT ONE BEING LOCATED OVER THE CENTRAL GULF OF MEXICO.  A
MID-LEVEL SHORT WAVE IS CURRENTLY NORTH OF THE DEPRESSION BUT WILL
SOON BE MOVING BY...WHICH SHOULD ALLOW THE WESTWARD DRIFT TO RESUME
LATER TODAY OR TONIGHT AS WEAK RIDGING BUILDS IN NORTH OF THE
CYCLONE.  GLOBAL MODELS GRADUALLY ERODE THE AREA OF HIGH PRESSURE
OVER THE GULF AS THE MID- TO UPPER-LEVEL LOW CURRENTLY OVER
SOUTHERN CALIFORNIA PROGRESSES EASTWARD.  MODEL GUIDANCE IS IN
REASONABLE AGREEMENT ON AN EVENTUAL TURN TO THE NORTHWEST AND THEN
NORTH AS THE RIDGE ERODES LATE IN THE FORECAST PERIOD...BUT WITH
SIGNIFICANT DIFFERENCES IN SPEED AS THE CYCLONE BEGINS TO
ACCELERATE.  THE OFFICIAL FORECAST IS JUST A SHADE FASTER THAN THE
PREVIOUS ADVISORY AND IS VERY CLOSE TO THE DYNAMICAL MODEL
CONSENSUS.
 

FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/1500Z 17.1N  79.3W    30 KT
 12HR VT     17/0000Z 17.1N  79.6W    35 KT
 24HR VT     17/1200Z 17.2N  80.0W    45 KT
 36HR VT     18/0000Z 17.3N  80.5W    55 KT
 48HR VT     18/1200Z 17.7N  81.2W    65 KT
 72HR VT     19/1200Z 18.5N  82.5W    80 KT
 96HR VT     20/1200Z 20.5N  84.0W    90 KT
120HR VT     21/1200Z 23.5N  84.5W    95 KT
 
 
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