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| #225825 (Received by flhurricane at: 5:23 PM 05.Nov.2008) TCDAT2 TROPICAL DEPRESSION SEVENTEEN DISCUSSION NUMBER 1...CORRECTED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL172008 400 PM EST WED NOV 05 2008 CORRECTED AWIPS BIN NUMBER 3 TO NUMBER 2 THE AREA OF DISTURBED WEATHER IN THE SOUTHWESTERN CARIBBEAN SEA HAS DEVELOPED ENOUGH ORGANIZED CONVECTION AND LOW-LEVEL CIRCULATION TO BE CONSIDERED A TROPICAL DEPRESSION. AN AIR FORCE HURRICANE HUNTER FOUND MAXIMUM WINDS OF 26 KT AT 1000 FT WITH A MINIMUM PRESSURE OF 1004 MB. SATELLITE IMAGES SHOW THAT MOST OF THE CONVECTION IS NORTHWEST OF THE CENTER BUT IS STARTING TO TAKE ON A BANDED APPEARANCE. THE INITIAL INTENSITY IS SET TO 25 KT IN ACCORDANCE WITH THE AIRCRAFT DATA AND NOAA BUOY 42057. ATMOSPHERIC AND OCEANIC PARAMETERS APPEAR TO BE VERY FAVORABLE FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS. IN FACT...THE GFDL AND HWRF TURN THE DEPRESSION INTO A MAJOR HURRICANE BEFORE CROSSING CUBA. IN CONTRAST...THE SHIPS/LGEM MODELS KEEP THE SYSTEM BELOW HURRICANE STRENGTH...WHICH SEEMS A LITTLE UNDERDONE GIVEN A LARGE UPPER ANTICYCLONE THAT ALL OF THE GLOBAL MODELS ARE FORMING NEAR THE DEPRESSION. THE OFFICIAL FORECAST WILL BE CLOSER TO THE DYNAMICAL GUIDANCE BUT NOT QUITE AS BULLISH AS THOSE MODELS FOR THE TIME BEING. NEAR THE END OF THE PERIOD...VERTICAL SHEAR IS FORECAST TO INCREASE DRAMATICALLY AND THIS COULD RESULT IN AN ABRUPT WEAKENING. A TWELVE-HOUR MOTION OF THIS SYSTEM IS ESTIMATED AT 305/4. A SLOW NORTHWEST TO NORTH MOVEMENT IS EXPECTED DURING THE NEXT DAY OR TWO AS THE DEPRESSION IS STEERED AROUND SOUTHWESTERN SIDE OF A MID- TROPOSPHERIC HIGH OVER THE NORTH-CENTRAL CARIBBEAN SEA. A DEEP TROUGH IS EXPECTED TO MOVE INTO THE GULF OF MEXICO IN ABOUT 3 DAYS...WHICH SHOULD CAUSE THE CYCLONE TO TURN TOWARD THE NORTHEAST AND ACCELERATE. THERE ARE SOME SIGNIFICANT SPEED DISCREPANCIES IN THE MODELS WITH THE GFDL/HWRF CONSIDERABLY FASTER THAN THE GFS/ECMWF/UKMET MODELS. LATE-SEASON TROPICAL CYCLONES ARE OFTEN NOTORIOUSLY SLOW-MOVING...E.G. MITCH OR WILMA...AND THE MODELS CAN BE TOO QUICK TO EJECT THESE SYSTEMS OUT OF THE CARIBBEAN. WE'RE GOING TO LEAN TOWARD THE SLOWER GUIDANCE AT THIS TIME...AND THE NHC FORECAST IS A BIT BEHIND THE DYNAMICAL MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 05/2100Z 14.0N 81.8W 25 KT 12HR VT 06/0600Z 14.3N 82.2W 30 KT 24HR VT 06/1800Z 14.8N 82.5W 40 KT 36HR VT 07/0600Z 15.5N 82.9W 50 KT 48HR VT 07/1800Z 16.5N 83.0W 65 KT 72HR VT 08/1800Z 18.0N 82.5W 75 KT 96HR VT 09/1800Z 19.5N 80.0W 75 KT 120HR VT 10/1800Z 21.5N 75.5W 50 KT $$ FORECASTER BRENNAN/STEWART |
