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#109621 (Received by flhurricane at: 11:03 PM 08.Sep.2006) TCDAT1 TROPICAL STORM FLORENCE DISCUSSION NUMBER 22 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062006 1100 PM EDT FRI SEP 08 2006 DURING THE EVENING...INNER-CORE CONVECTION ASSOCIATED WITH FLORENCE HAS CONSOLIDATED AND A CENTRAL DENSE OVERCAST APPEARS TO BE FORMING. CORRESPONDINGLY...DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB AT 0000Z SUGGEST 55 KT...WHILE 2119Z AMSU ANALYSES FROM CIRA AND CIMMS SUGGESTED A WEAKER SYSTEM AT THAT TIME. GIVEN THE INCREASED ORGANIZATION SEEN IN THE LAST FEW HOURS...THE INITIAL INTENSITY IS SET AT 55 KT. AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE FLORENCE IN A FEW HOURS AND PROVIDE A MORE ACCURATE ASSESSMENT OF BOTH ITS INTENSITY AND POSITION. THE INITIAL MOTION IS 305/13...THOUGH THIS IS SOMEWHAT UNCERTAIN GIVEN THE DIFFICULTY IN DETERMINING THE EXACT CENTER WITH INFRARED IMAGERY. FLORENCE IS ON THE SOUTHWEST PERIPHERY OF A DEEP-LAYER RIDGE AND IT SHOULD REACH ITS WESTERNMOST POINT IN ABOUT 36 TO 48 HOURS AS IT RECURVES INTO THE WESTERLIES. THE DYNAMICAL MODELS ARE TIGHTLY CLUSTERED THROUGH 72 HOURS AND NONE TAKE THE SYSTEM WEST OF 66W...SO IT APPEARS THAT THERE IS LITTLE DIRECT THREAT TO THE UNITED STATES OUTSIDE OF LARGE SWELLS AND SURF. BEYOND 72 HOURS...THERE IS A SIGNIFICANT SPREAD IN THE MODEL GUIDANCE WITH NOGAPS...GFDL AND ECMWF TO THE LEFT OF THE CONSENSUS...THE GFS SLOWER AND TO THE RIGHT...AND THE UKMET SIGNIFICANTLY FASTER. THE UKMET SOLUTION MAY BE ERRONEOUS GIVEN THAT THE OTHER MODELS SUGGEST A SECONDARY BAROCLINIC DEVELOPMENT IN THE REGION THAT THE UKMET CARRIES FLORENCE. THE FORECAST TRACK IS SLIGHTLY TO THE WEST OF THE PREVIOUS PREDICTION AND CLOSE TO THE MODEL CONSENSUS MINUS THE UKMET. GIVEN THE INNER-CORE DEVELOPMENT...WARM WATERS...LOW SHEAR AND ABUNDANT MOISTURE...FLORENCE SHOULD CONTINUE TO INTENSIFY OVER THE NEXT 48 HOURS. AFTER THAT TIME...COOLER WATERS...HIGHER SHEAR AND A MORE STABLE ATMOSPHERE SHOULD START THE WEAKENING PROCESS. HOWEVER...MOST GLOBAL MODELS SUGGEST THAT FLORENCE MAY BECOME A LARGE EXTRATROPICAL STORM AT DAYS FOUR AND FIVE. THE INTENSITY FORECAST IS CLOSE TO THE SHIPS AND FSU SUPER-ENSEMBLE GUIDANCE AND SOMEWHAT ABOVE GFDL. FORECAST POSITIONS AND MAX WINDS INITIAL 09/0300Z 24.5N 61.4W 55 KT 12HR VT 09/1200Z 25.5N 63.0W 65 KT 24HR VT 10/0000Z 27.0N 64.5W 75 KT 36HR VT 10/1200Z 28.7N 65.3W 85 KT 48HR VT 11/0000Z 30.7N 65.4W 90 KT 72HR VT 12/0000Z 35.5N 63.0W 85 KT 96HR VT 13/0000Z 42.5N 57.5W 75 KT...EXTRATROPICAL 120HR VT 14/0000Z 48.0N 48.0W 65 KT...EXTRATROPICAL $$ FORECASTER KNABB/LANDSEA |