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| #4893 (Received by flhurricane at: 5:21 PM 13.Aug.2004) TCDAT5 TROPICAL DEPRESSION FIVE DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT FRI AUG 13 2004 SATELLITE IMAGERY INDICATES THE VIGOROUS TROPICAL WAVE LOCATED ABOUT 910 NMI EAST-SOUTHEAST OF THE WINDWARD ISLANDS HAS BECOME MUCH BETTER ORGANIZED THIS AFTERNOON. THE SYSTEM IS BEING UPGRADED TO TROPICAL DEPRESSION FIVE BASED ON A CONSENSUS DVORAK SATELLITE INTENSITY ESTIMATE OF T1.5...OR 25 KT...AT 18Z...AND MUCH IMPROVED BANDING FEATURES SINCE THAT TIME. UPPER-LEVEL OUTFLOW IS FAIR IN ALL QUADRANTS. THE INITIAL MOTION ESTIMATE IS 280/17. THE DEPRESSION IS LOCATED AT A RATHER LOW LATITUDE FOR TROPICAL CYCLONE FORMATION TO OCCUR...BUT IT IS IN THE SAME GENERAL REGION THAT SPAWNED NOW MAJOR HURRICANE CHARLEY. THE SUBTROPICAL RIDGE TO THE NORTH OF THE DEPRESSION IS EXPECTED TO REMAIN INTACT THROUGHOUT THE FORECAST...AND THERE IS EXCELLENT AGREEMENT AMONG THE VARIOUS NHC MODELS ON THE CYCLONE MOVING IN A GENERAL WESTWARD MOTION FOR THE NEXT 12 TO 24 HOURS AND THEN WEST-NORTHWESTWARD AFTER THAT. WHILE THE GFDL MODEL MAKES A SHARP 30-40 DEGREE RIGHT TURN INITIALLY...THE WEST-NORTHWESTWARD MOTION AFTER 12 HOURS APPEARS QUITE REASONABLE. THE OFFICIAL TRACK IS CLOSE TO THE NHC MODEL CONSENSUS. ON THIS TRACK...THE CYCLONE COULD PASS THROUGH THE WINDWARD ISLANDS IN ABOUT 48 HOURS AS A TROPICAL STORM AND BE NEAR JAMAICA IN 120 HOURS AS A HURRICANE. THE SHIPS AND GFDL INTENSITY MODELS SHOW RATHER ROBUST DEVELOPMENT FOR THE FIRST 72 HOURS. THE GFDL MAKES THE CYCLONE A 75-KT HURRICANE IN 60 HOURS AND THEN UNCHARACTERISTICALLY LEVELS OFF THE INTENSITY AFTER THAT. THE SHIPS MODEL BRINGS THE INTENSITY UP STEADILY TO 93 KT IN 120 HOURS. GIVEN THE RATHER LARGE SIZE OF THE WIND FIELD AS NOTED IN AN EARLIER QUIKSCAT OVERPASS...MY FEELING IS THAT IT MAY TAKE THE WIND FIELD LONGER THAN USUAL TO CONTRACT DOWN IN SIZE...SO THE OFFICIAL INTENSITY FORECAST IS NOT AS BULLISH AS THE SHIPS MODEL. HOWEVER...THE VERTICAL SHEAR IS FORECAST TO REMAIN VERY LOW...SO SOME SIGNIFICANT INTENSIFICATION IS CERTAINLY POSSIBLE AFTER THE CYCLONE MOVES INTO THE VERY WARM CENTRAL CARIBBEAN SEA IN DAYS 4 AND 5. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 13/2100Z 8.9N 46.2W 30 KT 12HR VT 14/0600Z 9.5N 48.7W 35 KT 24HR VT 14/1800Z 10.3N 52.2W 40 KT 36HR VT 15/0600Z 11.1N 55.7W 45 KT 48HR VT 15/1800Z 12.1N 59.1W 55 KT 72HR VT 16/1800Z 14.0N 65.5W 65 KT 96HR VT 17/1800Z 16.0N 71.5W 70 KT 120HR VT 18/1800Z 18.5N 77.0W 80 KT |
