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| #52038 (Received by flhurricane at: 10:37 AM 16.Oct.2005) TCDAT4 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 |
