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| #210527 (Received by flhurricane at: 4:38 PM 25.Aug.2008) TCDAT2 TROPICAL STORM GUSTAV DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008 500 PM EDT MON AUG 25 2008 AFTER ITS RATHER RAPID INCREASE IN ORGANIZATION EARLIER TODAY...THE CLOUD PATTERN ASSOCIATED WITH GUSTAV HAS BECOME A LITTLE RAGGED-LOOKING...PARTICULARLY NEAR THE CENTER. THE AIR FORCE HURRICANE HUNTERS REPORTED A VERY SMALL AREA OF STRONG WINDS JUST TO THE SOUTHEAST OF THE CENTER WITH A PEAK FLIGHT LEVEL WIND SPEED OF 67 KT. USING A 75 PERCENT RATIO OF SURFACE TO FLIGHT LEVEL WINDS APPROPRIATE FOR THE 925 MB FLIGHT ALTITUDE GIVES 50 KT FOR THE INTENSITY ESTIMATE. ASSUMING THE CURRENTLY LESS-ORGANIZED APPEARANCE OF THE CYCLONE IS MERELY TEMPORARY...STRENGTHENING IS LIKELY GIVEN THE APPARENTLY FAVORABLE METEOROLOGICAL AND OCEANIC CONDITIONS. LATER IN THE FORECAST PERIOD...THE STRENGTH OF GUSTAV WILL OBVIOUSLY BE A STRONG FUNCTION OF HOW MUCH THE CIRCULATION INTERACTS WITH LAND. INTERESTINGLY...THE GFS CONTINUES TO FAIL TO SHOW DEVELOPMENT OF THE CYCLONE AND THE U.K. MET OFFICE GLOBAL MODEL SHOWS WEAKENING. THE INITIAL MOTION CONTINUES TOWARD THE NORTHWEST...315/12. THE GLOBAL MODELS DEPICT A MID-TROPOSPHERIC ANTICYCLONE CENTERED NEAR FLORIDA OVER THE NEXT SEVERAL DAYS. THE STEERING CURRENTS ASSOCIATED WITH THIS FEATURE SHOULD CAUSE THE MOTION OF GUSTAV TO GRADUALLY BEND TOWARD THE LEFT AND THIS IS ALSO SHOWN BY THE OFFICIAL TRACK FORECAST...WHICH IS SLIGHTLY WEST OF THE PREVIOUS ONE. SOME OF THE TRACK MODELS SUCH AS THE GFDL AND HWRF ARE TO THE LEFT OF THIS NHC FORECAST. NOTE THAT THERE IS SUBSTANTIAL UNCERTAINTY IN THE 4 AND 5 DAY FORECAST POSITIONS...AND ONE SHOULD NOT FOCUS ON THESE PRECISE POINTS. THE WIND RADII WERE DECREASED A LITTLE SINCE THE AIRCRAFT OBSERVATIONS SHOWED THAT GUSTAV IS A LITTLE SMALLER THAN EARLIER ESTIMATED. FORECAST POSITIONS AND MAX WINDS INITIAL 25/2100Z 16.3N 71.0W 50 KT 12HR VT 26/0600Z 17.2N 72.0W 60 KT 24HR VT 26/1800Z 18.4N 73.3W 65 KT...INLAND 36HR VT 27/0600Z 19.4N 74.4W 65 KT 48HR VT 27/1800Z 20.2N 75.5W 65 KT...INLAND 72HR VT 28/1800Z 21.3N 77.5W 55 KT...INLAND 96HR VT 29/1800Z 22.0N 79.0W 50 KT...INLAND 120HR VT 30/1800Z 23.0N 81.0W 50 KT...INLAND $$ FORECASTER PASCH |
