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#147178 (Received by flhurricane at: 11:08 PM 20.Aug.2007) TCDAT4 HURRICANE DEAN DISCUSSION NUMBER 32 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042007 1100 PM EDT MON AUG 20 2007 DEAN HAS TAPPED INTO ENERGY PROVIDED BY THE DEEP WARM WATERS OF THE NORTHWESTERN CARIBBEAN SEA THIS EVENING...AND HAS REACHED CATEGORY FIVE STATUS WITH AN INTENSITY OF 140 KT. DURING THE LAST PENETRATION BY THE AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT AT 00Z...A CENTRAL PRESSURE OF 914 MB WAS MEASURED. THE PEAK FLIGHT-LEVEL WIND WAS 162 KT...WHICH CORRESPONDS TO ABOUT 145 KT AT THE SURFACE. DUE TO COMMUNICATIONS PROBLEMS...WE HAVE NOT RECEIVED ALL OF THE DROPSONDE AND SFMR DATA IN REAL-TIME. THE ADVISORY INTENSITY IS SET TO A POSSIBLY CONSERVATIVE 140 KT...PENDING A MORE THOROUGH EXAMINATION OF ALL OF THE AIRCRAFT DATA. ANOTHER AIRCRAFT WILL ARRIVE IN THE EYE OF DEAN IN A FEW HOURS...PRIOR TO LANDFALL ALONG THE EAST COAST OF THE YUCATAN PENINSULA. THE EVOLVING SATELLITE PRESENTATION OF DEAN REVEALS AN INCREASINGLY SYMMETRIC CONVECTIVE PATTERN...AND A VERY WELL-DEFINED AND GRADUALLY CONTRACTING EYE WITH A DIAMETER OF ABOUT 20 N MI. REPORTS FROM THE AIRCRAFT...AND RECENT MICROWAVE SATELLITE IMAGERY...PROVIDE NO INDICATIONS OF ANY INNER-CORE STRUCTURAL CHANGES THAT WOULD LEAD TO WEAKENING PRIOR TO LANDFALL. THE OFFICIAL INTENSITY FORECAST IS ESSENTIALLY UNCHANGED. DEAN IS EXPECTED TO MAINTAIN HURRICANE STATUS DURING ITS ENTIRE STAY OVER YUCATAN...AND IT COULD STILL REGAIN MAJOR HURRICANE STATUS OVER THE BAY OF CAMPECHE BEFORE FINAL LANDFALL IN ABOUT 36 HOURS. THE HURRICANE GENERALLY REMAINS ON TRACK WITH AN INITIAL MOTION OF 275/17. A STRENGTHENING RIDGE OVER THE SOUTHEASTERN UNITED STATES SHOULD CONTINUE TO PUSH DEAN ROUGHLY ALONG THIS SAME HEADING AND SPEED FOR THE NEXT COUPLE OF DAYS UNTIL DISSIPATION OVER MAINLAND MEXICO. THE NEW OFFICIAL FORECAST IS AGAIN ADJUSTED TO THE SOUTH IN ORDER TO MAINTAIN THE CURRENT WELL-ESTABLISHED HEADING...AND TO BE IN BETTER AGREEMENT WITH A CONSENSUS OF THE GFDL...GFS...AND NOGAPS MODELS. ALONG THE NEW TRACK...DEAN WILL SPEND A LITTLE LESS TIME OVER THE BAY OF CAMPECHE...AND WILL PASS A LITTLE CLOSER TO THE NORTHERN COAST OF THE ISTHMUS OF TEHUANTEPEC DURING THE 24-36 HOUR PERIOD. AS A RESULT...NEW WATCHES AND WARNINGS HAVE BEEN ISSUED ALONG THE COAST OF MAINLAND MEXICO. FORECAST POSITIONS AND MAX WINDS INITIAL 21/0300Z 18.4N 86.0W 140 KT 12HR VT 21/1200Z 18.7N 88.6W 140 KT...INLAND OVER YUCATAN 24HR VT 22/0000Z 19.2N 92.1W 85 KT...BAY OF CAMPECHE 36HR VT 22/1200Z 19.6N 95.6W 95 KT...BAY OF CAMPECHE 48HR VT 23/0000Z 19.6N 99.1W 30 KT...INLAND OVER MEXICO 72HR VT 24/0000Z...DISSIPATED $$ FORECASTER KNABB/ROBERTS |