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#222485 (Received by flhurricane at: 11:17 AM 16.Oct.2008) TCDAT5 HURRICANE OMAR DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152008 1100 AM EDT THU OCT 16 2008 IT IS SIMPLY AMAZING TO ME AT HOW QUICKLY A HURRICANE CAN SPIN UP AND JUST AS QUICKLY FALL APART. OMAR REACHED NEAR THE THRESHOLD OF CATEGORY 4 EARLY THIS MORNING AROUND 06Z AND NOW WE HAVE AN EXPOSED LOW-LEVEL CENTER SHOWING UP IN THE VISIBLE SATELLITE IMAGERY JUST A FEW HOURS LATER. SUBJECTIVE AND OBJECTIVE DVORAK TECHNIQUES WERE SUGGESTING AROUND 90-100 KT AT 12Z. BUT GIVEN THE RAPID DETERIORATION OF THE CONVECTIVE SIGNATURE...THE CURRENT INTENSITY IS ESTIMATED...WITH SIGNIFICANT UNCERTAINTY...TO BE 75 KT. DESPITE VERY WARM WATERS...THE COMBINATION OF STRONG VERTICAL SHEAR AND LOW TO MID-LEVEL DRY AIR...AS SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY...HAS PRODUCED THE WEAKENING IN OMAR AND WILL LIKELY CONTINUE TO CAUSE A DECREASE IN ITS INTENSITY. BECAUSE THE TREND OF OMAR'S INTENSITY WAS NOT CORRECTLY ANALYZED AT SYNOPTIC TIME...THE STATISTICAL MODELS...SHIPS AND LGEM...ARE PROVIDING VALUES THAT ARE PROBABLY TOO HIGH. THE FORECAST IS CLOSEST TO THE HWRF MODEL WHICH DID VERY WELL IN ANTICIPATING THIS MORNING'S RAPID WEAKENING OF OMAR. AS THE CYCLONE BECOMES EXTRATROPICAL AROUND DAY 4...IT DOES NOT APPEAR THAT SIGNIFICANT RE-INTENSIFICATION WILL TAKE PLACE AT THAT TIME BASED UPON THE GLOBAL MODELS' CONSENSUS. THE NOW EASY-TO-SEE CENTER DID FORCE US TO MAKE A LAST SECOND RELOCATION OF THE INITIAL POSITION AS WELL AS THE SHORT TERM TRACK FORECAST TO ACCOUNT FOR THE MORE SOUTHERN LOCATION THAN AT FIRST ESTIMATED. THE TRACK GUIDANCE IS CLOSELY CLUSTERED THROUGH 72 HR...BUT THEN SHOWS SIGNIFICANT DIVERGENCE AT DAYS 4 AND 5. THE TRACK FORECAST IS A BLEND OF THE FASTER CONSENSUS OF THE GLOBAL AND HURRICANE MODELS AND THE SLOWER PREVIOUS ADVISORY. FORECAST POSITIONS AND MAX WINDS INITIAL 16/1500Z 20.2N 61.3W 75 KT 12HR VT 17/0000Z 23.5N 59.5W 70 KT 24HR VT 17/1200Z 28.0N 56.9W 65 KT 36HR VT 18/0000Z 31.3N 54.3W 60 KT 48HR VT 18/1200Z 33.4N 51.9W 55 KT 72HR VT 19/1200Z 38.0N 45.0W 55 KT 96HR VT 20/1200Z 40.0N 34.5W 50 KT...EXTRATROPICAL 120HR VT 21/1200Z 40.0N 23.0W 40 KT...EXTRATROPICAL $$ FORECASTER LANDSEA/STEWART |