000 WTPZ44 KNHC 111500 TCDEP4 HURRICANE FLOSSIE DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092007 800 AM PDT SAT AUG 11 2007 FLOSSIE HAS CONTINUED TO INTENSIFY THIS MORNING...WITH A MORE SYMMETRIC AND SOLID RING OF EYEWALL CLOUD TOPS NEAR -75C AROUND 12Z. ACCORDINGLY...SUBJECTIVE AND OBJECTIVE DVORAK INTENSITY ESTIMATES AT THAT TIME WERE A CONSENSUS T6.0 OR 115 KT...AND THAT IS THE ADVISORY INTENSITY. AN OVERPASS BY AMSR-E AT 1050Z REVEALS A SINGLE EYEWALL AND NO APPARENT SIGNS OF ANY IMPENDING INNER CORE STRUCTURAL CHANGES. SINCE 12Z THE INFRARED CLOUD TOP TEMPERATURES HAVE RISEN SLIGHTLY...SO IT IS POSSIBLE THAT THE HURRICANE HAS REACHED AN INTENSITY PLATEAU. THE UNDERLYING SEA-SURFACE TEMPERATURES ALONG THE FORECAST TRACK WILL BE COOLER FROM THIS POINT FORWARD...WHILE GLOBAL MODELS INDICATE THAT WIND SHEAR WILL BEGIN INCREASING IN ABOUT 72 HOURS. THEREFORE THE OFFICIAL FORECAST CALLS FOR FLOSSIE TO START GRADUALLY WEAKENING LATER TODAY...WITH THE PACE OF DECLINE PICKING UP WHEN THE SHEAR INCREASES ON DAY 3. THIS FORECAST IS CLOSE TO A CONSENSUS OF THE VARIOUS INTENSITY GUIDANCE MODELS. EXCEPT FOR THE FSSE...ALL OF THE INTENSITY GUIDANCE FORECASTS FLOSSIE TO DROP BELOW HURRICANE STATUS BEYOND 72 HOURS. THE HURRICANE CONTINUES DUE WESTWARD...AND THE INITIAL MOTION IS A SLIGHTLY WOBBLY 270 DEGREES AT 10 KNOTS. WE CAN SAY FOR SURE NOW THAT THE CENTER OF THE CYCLONE HAS CROSSED 140 DEGREES WEST INTO THE CENTRAL PACIFIC BASIN. ONCE AGAIN THE OFFICIAL TRACK FORECAST HAS NOT CHANGED APPRECIABLY AND REMAINS ROUGHLY IN THE MIDDLE OF THE GUIDANCE ENVELOPE. THE GUIDANCE SPREAD REMAINS LARGE... HOWEVER...ESPECIALLY LATE IN THE FORECAST PERIOD. THE EVENTUAL TRACK HINGES LARGELY ON JUST HOW STRONG THE SUBTROPICAL RIDGE IS TO THE NORTH OF FLOSSIE IN A FEW DAYS. MOST OF THE MODELS FORECAST THE RIDGE CURRENTLY CENTERED OVER HAWAII TO WEAKEN SOMEWHAT...WHICH SHOULD RESULT IN A TRACK THAT BENDS EVER SO GRADUALLY TO THE RIGHT. THE MAJORITY OF THE MODELS HOLD ONTO ENOUGH RIDGING TO KEEP THE CENTER OF A WEAKENING FLOSSIE SOUTH OF THE HAWAIIAN ISLANDS... ALTHOUGH A TRACK FARTHER NORTH THAN INDICATED BY THE OFFICIAL FORECAST CANNOT BE RULED OUT. THIS IS THE LAST ADVISORY ON FLOSSIE FROM THE NATIONAL HURRICANE CENTER. FUTURE ADVISORIES WILL BE ISSUED BY THE CENTRAL PACIFIC HURRICANE CENTER IN HONOLULU HAWAII. FORECAST POSITIONS AND MAX WINDS INITIAL 11/1500Z 12.7N 140.2W 115 KT 12HR VT 12/0000Z 12.9N 141.8W 115 KT 24HR VT 12/1200Z 13.3N 143.9W 105 KT 36HR VT 13/0000Z 13.7N 146.0W 95 KT 48HR VT 13/1200Z 14.1N 148.1W 85 KT 72HR VT 14/1200Z 15.5N 152.5W 70 KT 96HR VT 15/1200Z 17.0N 156.5W 55 KT 120HR VT 16/1200Z 18.5N 160.0W 45 KT $$ FORECASTER KNABB