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| #355306 (Received by flhurricane at: 10:55 PM 26.Jun.2010) TCDAT1 TROPICAL STORM ALEX DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010 1000 PM CDT SAT JUN 26 2010 SURFACE OBSERVATIONS AND RADAR IMAGERY FROM BELIZE INDICATE THAT THE CENTER OF ALEX MOVED INLAND IN THE PAST COUPLE OF HOURS JUST TO THE NORTH OF BELIZE CITY...WHERE RECENT OBSERVATIONS SERVE AS THE BASIS FOR THE CENTRAL PRESSURE OF 997 MB FOR THIS ADVISORY. WHILE DEEP CONVECTION HAS GENERALLY DECREASED OVER THE PAST FEW HOURS...A RECENT BURST DEVELOPED NEAR THE CENTER AS IT MOVED INLAND. GIVEN THIS...THE INITIAL INTENSITY IS LOWERED ONLY TO 50 KT...IN AGREEMENT WITH DVORAK CI ESTIMATES FROM TAFB AND SAB AT 0000 UTC. NOW THAT THE CENTER IS INLAND...WEAKENING SHOULD OCCUR OVERNIGHT AND EARLY SUNDAY AS ALEX MOVES ACROSS THE YUCATAN PENINSULA. AFTER ALEX MOVES INTO THE SOUTHERN GULF OF MEXICO...CONDITIONS APPEAR FAVORABLE FOR STRENGTHENING OVER WARM WATERS AND IN A LOW SHEAR ENVIRONMENT. THE OFFICIAL INTENSITY FORECAST IS CLOSE TO THE ICON INTENSITY CONSENSUS THROUGH THE PERIOD. THE INITIAL MOTION ESTIMATE IS 290/10...A LITTLE TO THE RIGHT OF THE PREVIOUS FORECAST. MOST OF THE TRACK MODEL GUIDANCE SHOWS A SUBTROPICAL RIDGE PERSISTING ACROSS THE NORTHERN GULF OF MEXICO... AND THESE MODELS TAKE ALEX ON A WEST OR WEST-NORTHWEST TRACK OVER THE SOUTHERN GULF AND INTO MEXICO IN 3 OR 4 DAYS. HOWEVER...THE LATEST RUNS OF THE GFDL AND GFS TAKE ALEX FARTHER NORTH LATE IN THE PERIOD...BUT THIS APPEARS TO BE DUE TO THE DEVELOPMENT OF SPURIOUS VORTICITY MAXIMA IN BOTH MODELS THAT ERODE THE RIDGE NORTH OF ALEX. GIVEN THEIR LACK OF CONTINUITY...THE GFS AND GFDL SOLUTIONS ARE CONSIDERED OUTLIERS. THE NEW OFFICIAL FORECAST IS ADJUSTED ONLY A LITTLE TO THE RIGHT OF THE PREVIOUS PACKAGE DUE TO THE INITIAL POSITION AND MOTION...AND IS IN GOOD AGREEMENT WITH A BLEND OF THE DYNAMICAL MODELS EXCLUDING THE GFDL AND GFS. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0300Z 17.7N 88.4W 50 KT 12HR VT 27/1200Z 18.5N 89.9W 30 KT...INLAND 24HR VT 28/0000Z 19.6N 91.5W 35 KT...OVER WATER 36HR VT 28/1200Z 20.4N 92.6W 45 KT 48HR VT 29/0000Z 21.0N 93.6W 55 KT 72HR VT 30/0000Z 22.0N 96.0W 70 KT 96HR VT 01/0000Z 23.0N 99.0W 55 KT...INLAND 120HR VT 02/0000Z 23.0N 101.5W 30 KT...INLAND $$ FORECASTER BRENNAN |
