000 WTPZ44 KNHC 260250 TCDEP4 HURRICANE FRANK DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092010 800 PM PDT WED AUG 25 2010 THE BANDING EYE-LIKE FEATURE THAT BRIEFLY APPEARED DURING THE AFTERNOON HAS SINCE DISAPPEARED BENEATH THE CIRRUS CANOPY. THE LATEST MICROWAVE IMAGERY CONTINUES TO REVEAL AN EYE AND HAS BEEN HELPFUL IN DETERMINING THE LOCATION AND INITIAL MOTION OF THE HURRICANE. THE INITIAL INTENSITY IS INCREASED TO 70 KT...BASED ON A BLEND OF SUBJECTIVE DVORAK DATA T-NUMBERS AND ADT ESTIMATES FROM UW/CIMSS. THE SHEAR HAS OBVIOUSLY WEAKENED SINCE YESTERDAY AND IS FORECAST TO REMAIN 15 KT OR LESS DURING THE NEXT COUPLE OF DAYS. SOME ADDITIONAL STRENGTHENING IS POSSIBLE DURING THE NEXT 24 HOURS AS FRANK REMAINS OVER WARM WATER. HOWEVER...THE INTENSITY GUIDANCE SHOWS LITTLE...IF ANY...ADDITIONAL INTENSIFICATION. AFTER 36 HOURS...STEADY WEAKENING IS ANTICIPATED AS THE CYCLONE MOVES OVER COOLER SSTS AND INTO A MORE STABLE ENVIRONMENT. THE INITIAL MOTION ESTIMATE IS 285/12 KT. FRANK IS EXPECTED TO CONTINUE ON A WEST-NORTHWESTWARD COURSE DURING THE NEXT DAY OR SO. IN 2-3 DAYS...THE CYCLONE IS FORECAST TO SLOW AND TURN NORTHWARD AS A MID-LATITUDE TROUGH DIGS SOUTHWARD OFF THE WEST COAST OF NORTH AMERICA. THE MODEL GUIDANCE IS QUITE DIVERGENT AT DAYS 4 AND 5 AS THE GFDL AND HWRF MODELS SHOW RECURVATURE TOWARD BAJA CALIFORNIA WHILE MOST OF THE GLOBAL MODELS TAKE THE CYCLONE SLOWLY NORTH OR NORTHWESTWARD. THE NHC FORECAST FOLLOWS THE LATTER SOLUTION. THE WIND RADII WERE ADJUSTED SLIGHTLY BASED ON ASCAT DATA THAT ARRIVED SHORTLY AFTER THE RELEASE OF THE PREVIOUS ADVISORY. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0300Z 17.2N 107.5W 70 KT 12HR VT 26/1200Z 17.6N 109.2W 75 KT 24HR VT 27/0000Z 18.1N 111.0W 75 KT 36HR VT 27/1200Z 18.5N 112.4W 70 KT 48HR VT 28/0000Z 19.1N 113.4W 60 KT 72HR VT 29/0000Z 20.3N 114.3W 50 KT 96HR VT 30/0000Z 21.3N 114.3W 35 KT 120HR VT 31/0000Z 22.5N 114.3W 25 KT...POST-TROP/REMNT LOW $$ FORECASTER BROWN