000 WTPZ43 KNHC 070244 TCDEP3 HURRICANE FELICIA DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP082009 800 PM PDT THU AUG 06 2009 FELICIA HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST SEVERAL HOURS....WITH A WELL-DEFINED EYE AND EYEWALL CLOUD TOPS COLDER THAN -70C IN SOME AREAS. SATELLITE INTENSITY ESTIMATES ARE 115 KT FROM TAFB AND SAB...AND THAT IS THE INITIAL INTENSITY FOR THIS ADVISORY. THE CIRRUS OUTFLOW IS GOOD IN THE WESTERN SEMICIRCLE AND FAIR ELSEWHERE. THE INITIAL MOTION IS 300/10. FELICIA IS ON THE SOUTH SIDE OF THE MID/UPPER-LEVEL SUBTROPICAL RIDGE...WITH A LARGE LOW-LEVEL RIDGE DOMINATING THE AREA NORTH AND WEST OF THE CYCLONE. WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW NEAR 23N153W. THE DYNAMICAL MODELS FORECAST THE LOW TO MOVE SLOWLY WESTWARD AND STRENGTHEN... CAUSING A BREAK IN THE MID/UPPER-LEVEL RIDGE EAST OF HAWAII AND A MID-LEVEL RIDGE TO DEVELOP NEAR THE HAWAIIAN ISLANDS. THE MOST LIKELY RESULT OF THIS EVOLUTION IS THAT AFTER 48 HR THE MID/UPPER- LEVEL CIRCULATION OF FELICIA WOULD HAVE ITS WESTWARD MOTION BLOCKED...WHILE THE LOW-LEVEL EASTERLY WINDS PUSHES THE LOW-LEVEL CENTER WESTWARD. THIS WOULD CAUSE FELICIA TO SHEAR APART AND THE REMAINING LOW-LEVEL CENTER TO MOVE GENERALLY WESTWARD. THE DYNAMICAL MODELS ARE IN GOOD AGREEMENT WITH THIS SCENARIO... ALTHOUGH WITH SOME SPREAD. THE GLOBAL MODELS...GFS...NOGAPS... UKMET...AND ECMWF...ARE ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE...WHILE THE HIGH-RESOLUTION HURRICANE MODELS...GFDL... HWRF...AND GFDN...ARE ON THE LEFT SIDE. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY...WITH A LITTLE MORE SOUTHWARD MOTION AFTER 72 HR OUT OF RESPECT FOR THE HIGH-RESOLUTION MODELS. THE TRACK IS NEAR THE CENTER OF THE GUIDANCE ENVELOPE. FELICIA IS CURRENTLY IN A LIGHT SHEAR ENVIRONMENT...AND THIS SHOULD CONTINUE FOR THE NEXT 48 HR OR SO. DURING THAT TIME...THE CYCLONE SHOULD WEAKEN AS IT MOVES OVER PROGRESSIVELY COOLER SEA SURFACE TEMPERATURES. BETWEEN 48-72 HR...VERTICAL WIND SHEAR IS FORECAST TO INCREASE AS FELICIA ENCOUNTERS THE WEATHER SYSTEMS DESCRIBED ABOVE AND ASSOCIATED UPPER-LEVEL WESTERLIES. THE DYNAMICAL MODELS SHOW THE MID/UPPER-LEVEL CIRCULATION OF FELICIA DISSIPATING AS THIS HAPPENS...WHICH OCCURS EVEN THOUGH THE FORECAST TRACK MOVES THE CYCLONE OVER WARMER SSTS DURING THAT TIME. THE INTENSITY FORECAST FOLLOWS THIS SCENARIO AND CALLS FOR FELICIA TO CONTINUE WEAKENING AFTER 48 HR. WARMER SSTS AND LESS-HOSTILE ATMOSPHERIC CONDITIONS ARE FORECAST SOUTH OF THE HAWAIIAN ISLANDS...AND IF FELICIA MOVES TO THE LEFT OF THE FORECAST TRACK THE AFTER-48 HR WEAKENING COULD BE SLOWER THAN CURRENTLY FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 07/0300Z 16.9N 133.6W 115 KT 12HR VT 07/1200Z 17.8N 134.9W 105 KT 24HR VT 08/0000Z 18.7N 136.6W 90 KT 36HR VT 08/1200Z 19.4N 138.9W 75 KT 48HR VT 09/0000Z 19.8N 141.5W 65 KT 72HR VT 10/0000Z 20.0N 147.0W 45 KT 96HR VT 11/0000Z 19.5N 152.5W 35 KT 120HR VT 12/0000Z 19.0N 157.5W 25 KT $$ FORECASTER BEVEN