000 WTPZ44 KNHC 251432 TCDEP4 HURRICANE FRANK DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092010 800 AM PDT WED AUG 25 2010 MICROWAVE IMAGERY DURING THE PAST 6 HOURS INDICATES FRANK HAS BECOME MUCH BETTER ORGANIZED AND THAT THE CENTER IS EMBEDDED NEAR THE MIDDLE OF A VERY COLD CDO WITH CLOUD TOPS OF -80C TO -86C. SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T4.0/65 KT FROM TAFB AND SAB...ALTHOUGH DATA-T NUMBERS WERE A CONSENSUS T5.0/90 KT. THEREFORE...FRANK IS UPGRADED TO A 65-KT HURRICANE. FRANK REMAINS ON TRACK AND THE INITIAL MOTION ESTIMATE IS 285/09. HURRICANE FRANK IS EXPECTED TO MOVE WEST-NORTHWESTWARD AT A STEADY PACE FOR THE NEXT 3 DAYS AROUND THE SOUTHERN PERIPHERY OF A STRONG SUBTROPICAL RIDGE SITUATED OVER NORTHERN MEXICO AND THE SOUTHWESTERN UNITED STATES. BY DAYS 4 AND 5...A MID-LATITUDE TROUGH IS FORECAST BY ALL OF THE MODELS TO DIG SOUTHWARD OFF THE WEST COAST OF THE U.S. AND BAJA CALIFORNIA...WHICH SHOULD ACT TO ERODE THE WESTERN PORTION OF THE RIDGE. AS THE STEERING FLOW WEAKENS... FRANK IS EXPECTED TO SLOWLY TURN NORTHWARD AND POSSIBLY BEGIN RECURVATURE TO THE NORTHEAST AS A WEAKENING TROPICAL STORM. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND REMAINS A LITTLE TO THE RIGHT OF THE MODEL CONSENSUS. AN 0834 UTC AMSR MICROWAVE PASS INDICATED FRANK HAD A CLOSED LOW- AND MID-LEVEL EYE WITH TIGHTLY CURVED BANDING FEATURES IN ALL QUADRANTS. THE GFS AND ECMWF STILL INDICATE AN IMPRESSIVE OUTFLOW PATTERN IS EXPECTED TO DEVELOP OVER FRANK DURING THE NEXT 36 HOURS. BOTH MODELS ARE ALSO FORECASTING FRANK TO STRENGTHEN VERTICALLY AS DEPICTED BY A 45-55 KT CYCLONIC 200 MB CIRCULATION BY 24 HOURS. THIS FEATURE WOULD GENERALLY INDICATE A SIGNIFICANT HURRICANE...BUT THE GFS-BASED SHIPS MODEL ONLY BRINGS FRANK UP TO 76 KT. THE GFDL IS ABOUT 10 KT HIGHER. BY 72 HOURS...FRANK IS EXPECTED TO BE MOVING OVER MUCH COOLER WATER... WHICH SHOULD INDUCE A STEADY WEAKENING TREND. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE VARIOUS INTENSITY MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 25/1500Z 16.6N 104.8W 65 KT 12HR VT 26/0000Z 17.0N 106.2W 70 KT 24HR VT 26/1200Z 17.6N 108.0W 75 KT 36HR VT 27/0000Z 18.2N 109.8W 75 KT 48HR VT 27/1200Z 18.8N 111.5W 65 KT 72HR VT 28/1200Z 19.9N 113.2W 55 KT 96HR VT 29/1200Z 21.0N 113.8W 45 KT 120HR VT 30/1200Z 22.5N 113.5W 35 KT $$ FORECASTER STEWART