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| #222386 (Received by flhurricane at: 11:17 PM 15.Oct.2008) TCDAT5 HURRICANE OMAR DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152008 1100 PM EDT WED OCT 15 2008 JUST-RECEIVED DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER INVESTIGATING OMAR SHOWED 700 MB FLIGHT-LEVEL WINDS OF 117 KT...AND AN ESTIMATED SURFACE WIND FROM THE SFMR OF 108 KT IN THE SOUTHEASTERN EYEWALL. THE CENTRAL PRESSURE WAS 967 MB. ON THIS BASIS...OMAR IS UPGRADED TO A 100-KT MAJOR HURRICANE...AND THE INITIAL INTENSITY COULD BE CONSERVATIVE. SATELLITE AND RADAR DATA ARE CONSISTENT WITH THE AIRCRAFT-REPORTED INTENSIFICATION...SHOWING INCREASED ORGANIZATION IN BOTH THE EYE AND EYEWALL. OMAR HAS ACCELERATED DURING THE PAST FEW HOURS AND THE INITIAL MOTION IS NOW 050/17. IN THE SHORT TERM...THE MODEL GUIDANCE KEEPS FORECASTING A 15-20 DEGREE LEFT TURN THAT SO FAR HAS NOT OCCURRED. OTHER THAN THAT...THE TRACK FORECAST IS STRAIGHT FORWARD. OMAR IS EMBEDDED IN MID/UPPER-LEVEL SOUTHWESTERLY FLOW TO THE SOUTH OF A LARGE TROUGH OVER THE MID-ATLANTIC. WHILE THE LARGE-SCALE MODELS FORECAST THIS TROUGH TO LIFT OUT TO THE NORTHEAST DURING THE NEXT 48 HOURS...THEY FORECAST A SECOND TROUGH TO MOVE EASTWARD INTO THE WESTERN ATLANTIC BY 96 HOURS. THIS PATTERN EVOLUTION SHOULD KEEP OMAR ON A GENERAL NORTHEASTERLY COURSE WITH SOME VARIATION IN SPEED DURING THE NEXT 72 HOURS...FOLLOWED BY A MORE EASTWARD MOTION WITH ACCELERATION AS THE CYCLONE ENTERS THE CORE OF THE WESTERLIES. THE FORECAST GUIDANCE IS TIGHTLY CLUSTERED THROUGH 72 HOURS...WITH SOME SPREAD IN BOTH SPEED AND DIRECTION AFTER THAT TIME. THE NEW FORECAST TRACK IS A LITTLE FASTER THAN THE PREVIOUS TRACK THROUGH THE FIRST 72 HOURS AND A LITTLE SLOWER AT 96 AND 120 HOURS. THIS FORECAST IS DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE. THE FORECAST TRACK TAKES OMAR OVER DECREASING SEA SURFACE TEMPERATURES AND INTO INCREASING VERTICAL WIND SHEAR AFTER ABOUT 24 HOURS. THIS SUGGESTS THAT THE HURRICANE HAS A SMALL WINDOW OF OPPORTUNITY IN WHICH TO INTENSIFY...AND THE INTENSITY FORECAST CALLS FOR OMAR TO PEAK AT 105 KT IN ABOUT 12 HOURS. THEREAFTER... OMAR SHOULD GRADUALLY WEAKEN...WITH THE STORM UNDERGOING EXTRATROPICAL TRANSITION STARTING AT ABOUT 96 HOURS. IT IS IMPORTANT TO REMEMBER THAT STRONGER WINDS...POSSIBLY ONE CATEGORY HIGHER...CAN BE EXPECTED OVER HIGHER TERRAIN...ESPECIALLY ABOVE 500 FT ELEVATION. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 17.4N 64.5W 100 KT 12HR VT 16/1200Z 19.4N 63.1W 105 KT 24HR VT 17/0000Z 22.2N 61.2W 100 KT 36HR VT 17/1200Z 25.0N 59.3W 90 KT 48HR VT 18/0000Z 27.6N 57.5W 80 KT 72HR VT 19/0000Z 34.0N 53.0W 65 KT 96HR VT 20/0000Z 41.0N 41.5W 55 KT...BECOMING EXTRATROPICAL 120HR VT 21/0000Z 47.0N 25.0W 50 KT...EXTRATROPICAL $$ FORECASTER BEVEN |
