000 WTNT44 KNHC 181454 TCDAT4 HURRICANE WILMA DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT TUE OCT 18 2005 WILMA IS BEING UPGRADED TO A HURRICANE BASED ON SUBJECTIVE DVORAK CLASSIFICATIONS OF T4.0 FROM ALL AGENCIES...AND OBJECTIVE T NUMBERS FROM UW/CIMSS OF T4.5 SINCE 09Z. ANOTHER RECONNAISSANCE AIRCRAFT IS SCHEDULED TO BE IN THE SYSTEM THIS AFTERNOON. COLD CONVECTION IS BEING MAINTAINED OVER THE CENTER...AND STRONG UPPER-LEVEL OUTFLOW CHANNELS CONTINUE TO THE NORTHEAST AND SOUTHWEST OF THE CENTER. OCEANIC HEAT CONTENT AHEAD OF WILMA IS HIGH. THE ONLY INHIBITING FACTOR IS THE DRY AIR MASS IN THE GULF AND EXTREME NORTHWESTERN CARIBBEAN...BUT THE LARGE AND GROWING CIRCULATION OF WILMA SHOULD BE ABLE TO KEEP MUCH OF THIS AIR FROM REACHING THE CORE. A HIGH LIKELIHOOD OF RAPID STRENGTHENING IS INDICATED BY THE SHIPS RAPID INTENSIFICATION INDEX...AND IT IS LIKELY THAT WILMA WILL BE A MAJOR HURRICANE WHEN IT ENTERS THE SOUTHEASTERN GULF OF MEXICO. AS WILMA ACCELERATES NORTHEASTWARD LATE IN THE FORECAST PERIOD...WIND SHEAR IS FORECAST TO INCREASE...BUT THERE MAY NOT BE ENOUGH OF IT TO WEAKEN WILMA VERY QUICKLY. HOWEVER...IT IS WORTH REMEMBERING THAT THERE IS LITTLE SKILL IN LONG-RANGE INTENSITY FORECASTS. THE INITIAL MOTION IS ESTIMATED TO BE 320/5. THERE HAS BEEN LITTLE CHANGE TO THE TRACK FORECAST THINKING. THE MID- TO UPPER-LEVEL LOW THAT HAD BEEN OFF THE SOUTHERN CALIFORNIA COAST IS NOW MOVING NORTHEASTWARD...AND AS IT PROGRESSES HIGH PRESSURE OVER THE GULF OF MEXICO IS EXPECTED TO WEAKEN...ALLOWING WILMA TO MOVE THROUGH THE NORTHWESTERN CARIBBEAN AND ENTER THE SOUTHEASTERN GULF OF MEXICO IN ABOUT THREE DAYS. ONCE WILMA MOVES NORTH OF THE SUBTROPICAL RIDGE AXIS AND ENCOUNTERS MID-LEVEL WESTERLY FLOW...AN ACCELERATION NORTHEASTWARD IS EXPECTED. MODEL GUIDANCE HAS NOT CHANGED MUCH AND REMAINS IN VERY GOOD AGREEMENT...AND THE OFFICIAL FORECAST IS VERY SIMILAR TO THE PREVIOUS ADVISORY AND CLOSE TO THE DYNAMICAL MODEL CONSENSUS. WILMA...THE 12TH HURRICANE OF THE SEASON...TIES THE RECORD FOR MOST HURRICANES IN A SEASON SET IN 1969. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 18/1500Z 16.5N 80.6W 65 KT 12HR VT 19/0000Z 17.0N 81.2W 75 KT 24HR VT 19/1200Z 17.7N 82.3W 90 KT 36HR VT 20/0000Z 18.5N 83.5W 100 KT 48HR VT 20/1200Z 19.6N 84.5W 105 KT 72HR VT 21/1200Z 22.0N 85.5W 105 KT 96HR VT 22/1200Z 24.0N 84.0W 100 KT 120HR VT 23/1200Z 28.5N 78.5W 75 KT $$