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| #146896 (Received by flhurricane at: 4:55 AM 19.Aug.2007) TCDAT4 HURRICANE DEAN DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042007 500 AM EDT SUN AUG 19 2007 THE LAST PENETRATION OF THE EYE OF THE HURRICANE BY THE AIR FORCE HURRICANE HUNTERS WAS AT 0511 UTC. THE AIRCRAFT REPORTED A MINIMUM PRESSURE OF 921 MB BY DROPSONDE AND PEAK FLIGHT-LEVEL WINDS OF 130 KT OUTBOUND IN THE NORTHEAST QUADRANT. SATELLITE IMAGERY SHOWS A LESS DISTINCT EYE WITH SOME WARMING OF THE SURROUNDING CLOUD TOPS...ALTHOUGH THE CLOUD PATTERN REMAINS VERY IMPRESSIVE WITH GOOD SYMMETRY AND STRONG OUTFLOW OVER ALL QUADRANTS. THE INITIAL INTENSITY ESTIMATE IS KEPT AT 125 KT FOR THIS ADVISORY...WHICH MAY BE A LITTLE ON THE HIGH SIDE. IF INDEED DEAN HAS WEAKENED...THIS IS LIKELY THE RESULT OF INNER CORE PROCESSES...AND IS PROBABLY ONLY A SHORT-TERM CHANGE. THE LARGE-SCALE ATMOSPHERIC AND OCEANIC ENVIRONMENT STILL APPEAR TO BE VERY FAVORABLE FOR STRENGTHENING... SO....ASIDE FROM INNER-CORE-RELATED FLUCTUATIONS...DEAN HAS THE POTENTIAL TO ATTAIN CATEGORY FIVE HURRICANE STATUS OVER THE NORTHWESTERN CARIBBEAN SEA. THIS IS SUPPORTED BY THE GFDL... SHIPS...LGEM...AND FSSE GUIDANCE. INTERACTION WITH THE YUCATAN PENINSULA WILL CAUSE WEAKENING...AND THE AMOUNT OF RE-STRENGTHENING OF DEAN OVER THE SOUTHWESTERN GULF OF MEXICO DEPENDS MAINLY ON HOW LONG THE SYSTEM STAYS OVER WATER BEFORE MAKING ITS FINAL LANDFALL. ASIDE FROM THE TROCHOIDAL WOBBLES THAT ARE COMMON WITH SUCH INTENSE HURRICANES...THE MOTION HAS BEEN BETWEEN WEST AND WEST-NORTHWEST OVER THE PAST 12-24 HOURS. INITIAL MOTION ESTIMATE IS 285/16. AS THE MID- TO UPPER-LEVEL CYCLONE OVER THE EASTERN GULF OF MEXICO CONTINUES TO SHIFT WESTWARD AHEAD OF DEAN...THE FUTURE TRACK OF THE HURRICANE WILL BE CONTROLLED LARGELY BY A DEEP-LAYER HIGH PRESSURE SYSTEM THAT IS FORECAST TO BUILD OVER THE SOUTHEASTERN UNITED STATES. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON A CONTINUED WEST-NORTHWESTWARD MOTION THROUGHOUT THE FORECAST PERIOD. ANY CHANGES FROM THE PREVIOUS OFFICIAL TRACK FORECAST DURING THE FIRST 48 HOURS OR SO SHOULD BE CONSIDERED COSMETIC. WE HAVE SHIFTED THE OFFICIAL FORECAST TRACK SLIGHTLY SOUTHWARD IN THE LATTER PART OF THE PERIOD...BUT NOT AS FAR SOUTH AS SHOWN BY THE GFS...U.K. MET. AND ECMWF MODELS. IT IS IMPERATIVE NOT TO FOCUS ON THE EXACT FORECAST TRACK. CONSIDERING THE MARGIN OF ERROR OF NHC PREDICTIONS...THE CORE OF THIS LARGE HURRICANE COULD EASILY BE 30-50 N MI ON EITHER SIDE OF THE FORECAST TRACK DURING THE NEXT 12 HOURS OR SO. ANOTHER AIR FORCE RECONNAISSANCE PLANE IS SCHEDULED TO MAKE A POSITION AND INTENSITY FIX ON DEAN AROUND 1200 UTC. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 16.6N 73.4W 125 KT 12HR VT 19/1800Z 17.1N 76.0W 130 KT 24HR VT 20/0600Z 17.9N 79.5W 130 KT 36HR VT 20/1800Z 18.7N 83.0W 135 KT 48HR VT 21/0600Z 19.5N 86.6W 140 KT 72HR VT 22/0600Z 21.0N 93.5W 85 KT 96HR VT 23/0600Z 22.5N 99.0W 50 KT...INLAND 120HR VT 24/0600Z 23.5N 103.0W 25 KT...INLAND $$ FORECASTER PASCH/BROWN |
