000 WTNT41 KNHC 060242 TCDAT1 TROPICAL STORM FLORENCE DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012 1100 PM AST SUN AUG 05 2012 FLORENCE HAD BEEN DEVOID OF DEEP CONVECTION FOR A WHILE UNTIL A BURST OF DISORGANIZED THUNDERSTORMS FORMED WELL SOUTHWEST OF THE CENTER IN THE PAST FEW HOURS. EUMETSAT RGB SATELLITE IMAGERY CONTINUES TO SHOW A LARGE MASS OF SAHARAN AIR WRAPPING AROUND THE TROPICAL CYCLONE CIRCULATION. THE DRY AIR...COMBINED WITH THE EFFECTS OF SOME EASTERLY SHEAR AND ONLY MARGINALLY WARM WATERS... HAS MADE IT DIFFICULT FOR FLORENCE TO MAINTAIN ANY SIGNIFICANT CONVECTION. DVORAK INTENSITY ESTIMATES CONTINUE TO DECREASE...AND THE INITIAL INTENSITY IS LOWERED TO 35 KT BASED ON A BLEND OF DVORAK T- AND CI-NUMBERS FROM TAFB. EVEN THOUGH THE STORM WILL BE MOVING INTO WARMER WATERS DURING THE NEXT FEW DAYS...DRY AIR WILL CONTINUE TO DOMINATE THE NEAR-STORM ENVIRONMENT. WESTERLY VERTICAL SHEAR IS ALSO FORECAST TO INCREASE OVER FLORENCE AS THE CYCLONE ENCOUNTERS A PRONOUNCED UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC. THE OFFICIAL NHC FORECAST IS SIMILAR TO THE PREVIOUS ONE...CALLING FOR FLORENCE TO DEGENERATE INTO A REMNANT LOW IN 72 HOURS. THIS FORECAST AGREES WELL WITH THE LATEST DYNAMICAL INTENSITY GUIDANCE AND GLOBAL MODELS...THE LATTER OF WHICH FORECAST DISSIPATION. IT SHOULD BE NOTED THAT THE STATISTICAL GUIDANCE...WHICH IS BEING DISCOUNTED...SHOWS A REMOTE POSSIBILITY OF REGENERATION LATE IN THE FORECAST PERIOD. THE INITIAL MOTION ESTIMATE IS 270/11 KT. LARGE-SCALE MODELS SHOW FLORENCE MOVING QUICKLY ON A GENERALLY WESTWARD COURSE DURING THE NEXT FEW DAYS...UNDER THE INFLUENCE OF A BUILDING LOW- TO MID-LEVEL RIDGE TO THE NORTH. THE TRACK OF FLORENCE SHOULD BEND TOWARD THE WEST-NORTHWEST AFTER 72 HOURS AS THE CYCLONE ROUNDS THE SOUTHWEST PERIPHERY OF THE RIDGE. THE MODEL GUIDANCE HAS SHIFTED SOUTHWARD THIS CYCLE...AND THE NEW FORECAST IS THEREFORE ADJUSTED IN THAT DIRECTION...LYING CLOSE TO THE MULTI-MODEL CONSENSUS AND IN THE MIDDLE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 16.2N 37.9W 35 KT 40 MPH 12H 06/1200Z 16.3N 39.9W 30 KT 35 MPH 24H 07/0000Z 16.7N 43.0W 30 KT 35 MPH 36H 07/1200Z 17.3N 46.4W 30 KT 35 MPH 48H 08/0000Z 18.1N 50.0W 30 KT 35 MPH 72H 09/0000Z 19.9N 57.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 10/0000Z 22.0N 62.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 11/0000Z 25.0N 67.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER KIMBERLAIN