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| #222140 (Received by flhurricane at: 5:03 PM 14.Oct.2008) TCDAT5 TROPICAL STORM OMAR DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152008 500 PM EDT TUE OCT 14 2008 SATELLITE...RADAR...AND AIR FORCE RECON DATA INDICATE THAT OMAR HAS RAPIDLY INTENSIFIED THIS AFTERNOON. ALTHOUGH MAXIMUM 850 MB FLIGHT-LEVEL WINDS OBSERVED HAVE ONLY BEEN 63 KT...RELIABLE SFMR SURFACE WIND DATA HAVE BEEN AS HIGH 57-60 KT ON THE SOUTH SIDE OF THE CIRCULATION CENTER. THE LOWEST CENTRAL PRESSURE MEASURED BY A DROPSONDE WAS 986 MB...BUT THE SURFACE WIND WAS 46 KT. THEREFORE... THE PRESSURE IS ESTIMATED TO BE 982 MB AND THE INTENSITY HAS BEEN INCREASED TO A CONSERVATIVE 60 KT. OMAR CONTINUES TO GET BETTER ORGANIZED IN BOTH RADAR AND SATELLITE IMAGERY...AND VERY COLD CLOUD TOPS OF -80C TO -87C PERSIST OVER AND NEAR THE CIRCULATION CENTER. ON THE LAST PASS THROUGH THE CENTER OF OMAR...THE FLIGHT CREW REPORTED A 10-15 NMI DIAMETER EYE WAS FORMING. OUTFLOW ALSO CONTINUES TO IMPROVE AND EXPAND IN ALL QUADRANTS...EXCEPT TO THE NORTHWEST WHERE IT IS SLIGHTLY RESTRICTED. THE INITIAL MOTION ESTIMATE IS NOW 060/06. THE THREE RECON FIXES THIS AFTERNOON SUGGEST THAT OMAR MAY BE FINALLY MAKING THE TURN TO THE NORTHEAST THAT THE MODELS HAVE BEEN FORECASTING FOR THE PAST SEVERAL CYCLES. ALL OF THE AVAILABLE MODEL GUIDANCE IS TIGHTLY CLUSTERED ON A TRACK THROUGH THE NORTHERN LEEWARD ISLANDS IN ABOUT 36 HOURS...WITH SIGNIFICANT ACCELERATION EXPECTED AFTER THAT AS OMAR GETS LIFTED RAPIDLY NORTHEASTWARD AHEAD OF A DIGGING MID-TROPOSPHERIC TROUGH THAT COVERS MOST OF THE CENTRAL AND WESTERN ATLANTIC. THE MAIN DIFFERENCE BETWEEN THE MODELS IS IN THE FORWARD SPEED OF OMAR AFTER 24 HOURS. THE GFS...GFDL...AND HWRF MODELS RACE OMAR QUICKLY TO THE NORTHEAST...WHEREAS THE UKMET AND ECMWF MODELS ARE NOTICEABLY SLOWER. THE OFFICIAL FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY TO THE EAST OF THE PREVIOUS TRACK THROUGH 36 HOURS...BUT REMAINS JUST TO THE WEST OF AND SLOWER THAN THE MODEL CONSENSUS. ADDITIONAL STRENGTHENING...POSSIBLY EVEN RAPID INTENSIFICATION... IS EXPECTED SINCE THE ENVIRONMENT IS NOT FORECAST TO CHANGE MUCH IN THE NEXT DAY OR SO. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE SHIPS...GFDL... AND HWRF MODELS...AND OMAR IS EXPECTED TO OBTAIN CATEGORY 2 STRENGTH BY THE TIME IT REACHES THE NORTHERN LEEWARD ISLANDS IN ABOUT 36 HOURS. IT IS WORTH NOTING THAT THE SHIPS MODEL BRINGS OMAR TO 104 KT BY 48 HOURS. HOWEVER...THE 12Z HWRF MODEL ONLY BRINGS OMAR TO 88 KT AND THE GFDL ONLY STRENGTHENS THE CYCLONE TO 62 KT. BASED ON A STRONGER VORTEX INITIALIZED BY THE MODELS FOR THE 18Z CYCLE...OUTPUT FROM THOSE MODELS DUE OUT IN A FEW HOURS MAY BE QUITE DIFFERENT AND MUCH STRONGER. AS A RESULT... SUBSEQUENT NHC INTENSITY FORECASTS MAY HAVE TO BE ADJUSTED UPWARD. FORECAST POSITIONS AND MAX WINDS INITIAL 14/2100Z 14.0N 68.5W 60 KT 12HR VT 15/0600Z 14.6N 68.0W 70 KT 24HR VT 15/1800Z 15.9N 66.4W 80 KT 36HR VT 16/0600Z 18.0N 64.3W 85 KT 48HR VT 16/1800Z 20.6N 62.1W 85 KT 72HR VT 17/1800Z 26.0N 58.4W 80 KT 96HR VT 18/1800Z 31.1N 55.5W 70 KT 120HR VT 19/1800Z 38.0N 49.0W 60 KT $$ FORECASTER STEWART |
