000 WTPZ43 KNHC 210848 TCDEP3 TROPICAL STORM KENNETH DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132011 100 AM PST MON NOV 21 2011 INFRARED AND MICROWAVE SATELLITE IMAGERY INDICATE THE CONVECTIVE BANDING AND AMOUNT OF DEEP CONVECTION ASSOCIATED WITH KENNETH HAS SHARPLY INCREASED DURING THE PAST 6 HOURS...INCLUDING THE BRIEF APPEARANCE OF A MID-LEVEL EYE FEATURE. SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T3.5 FROM TAFB AND SAB...AND THE MOST RECENT 2-HOUR AVERAGE ADT VALUE FROM UW-CIMSS IS ALSO T3.5/55 KT. BASED ON THIS INFORMATION...THE INITIAL INTENSITY IS SET TO 55 KT. THE INITIAL MOTION ESTIMATE IS 280/12 KT. THE CENTER OF CIRCULATION APPEARS TO HAVE FINALLY STABILIZED WITHIN THE CONVECTIVE CLOUD MASS AND MICROWAVE FIXES INDICATE KENNETH HAS BEEN MOVING MORE WESTWARD DURING THE PAST 9 HOURS. OTHERWISE...THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. THE STRONG SUBTROPICAL RIDGE TO THE NORTH OF KENNETH IS FORECAST TO REMAIN BASICALLY INTACT THROUGHOUT THE FORECAST PERIOD WITH ONLY MINOR WEAKENING OF THE RIDGE EXPECTED IN 72-84 HOURS WHEN A STRONG SHORTWAVE TROUGH IS FORECAST TO PASS NORTH OF THE CYCLONE ALONG 120W LONGITUDE. WATER VAPOR IMAGERY INDICATES A LONG FETCH OF VERY FAST WEST TO WEST-SOUTHWESTERLY MID-/UPPER-LEVEL FLOW ACROSS THE CENTRAL AND EASTERN PACIFIC. THIS TYPE OF LOWER AMPLITUDE PATTERNS FAVORS TROUGHS MOVING QUICKLY EASTWARD RATHER THAN DIGGING SOUTHEASTWARD. THE LATEST 00Z GFS RUN HAS NOW BACKED OFF ON WEAKENING THE RIDGE AND ALLOWING KENNETH TO RECURVE NORTHWARD INTO THE MID-LATITUDE WESTERLIES. ONLY THE HWRF MODEL HAS CONTINUED THE TREND OF RECURVING KENNETH...WHICH NOW APPEARS TO BE AN OUTLIER SCENARIO SINCE ALL OF THE GLOBAL MODELS...AND THE GFDL AND HFIP MODELS... KEEP KENNETH AS A STRAIGHT-RUNNER TYPE CYCLONE FOR THE NEXT 5 DAYS. THE OFFICIAL FORECAST TRACK IS SIMILAR TO BUT SLIGHTLY SOUTH OF THE PREVIOUS ADVISORY...AND REMAINS SOUTH OF THE HWRF-BIASED CONSENSUS MODELS...ESPECIALLY AFTER 72 HOURS. KENNETH HAS BEEN RAPIDLY INTENSIFYING FOR THE PAST 12 HOURS AND THIS TREND COULD CONTINUE FOR ANOTHER 12-18 HOURS GIVEN THE LOW VERTICAL SHEAR CONDITIONS EXPECTED. HOWEVER...A WELL PRONOUNCED DRY SLOT HAS DEVELOPED IN THE EASTERN SEMICIRCLE AND HAS WRAPPED INTO THE INNER CORE...AND THIS DRY AIR COULD BRIEFLY INTERRUPT THE STRENGTHENING PROCESS. REGARDLESS OF THE EFFECTS OF DRY AIR...KENNETH IS EXPECTED TO BECOME A HURRICANE WITHIN THE NEXT 12-24 HOURS...AND STEADY INTENSIFICATION IS FORECAST FOR THE NEXT 36-48 HOURS WHILE THE CYCLONE REMAINS OVER WARM WATER AND IN A LOW SHEAR AND MOIST SURROUNDING ENVIRONMENT. BY 72 HOURS...HOWEVER...COOLER WATER BENEATH THE CYCLONE SHOULD BEGIN TO INDUCE GRADUAL WEAKENING...AND INCREASING SOUTHERLY TO SOUTHWESTERLY UPPER-LEVEL SHEAR BY DAYS 4 AND 5 SHOULD INDUCE MORE RAPID WEAKENING. THE INTENSITY FORECAST IS SOMEWHAT HIGHER THAN THE PREVIOUS ADVISORY...AND FOLLOWS A BLEND OF THE LGEM AND THE MORE ROBUST HWRF/GFDL MODELS. THE 12-FT SEAS RADII WERE EXPANDED IN THE NORTHERN SEMICIRCLE BASED ON REPORTS FROM SHIP LAXS2 LOCATED IN THE NORTHEASTERN QUADRANT. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 12.3N 108.4W 55 KT 65 MPH 12H 21/1800Z 12.6N 110.1W 65 KT 75 MPH 24H 22/0600Z 12.8N 112.2W 75 KT 85 MPH 36H 22/1800Z 12.8N 114.3W 80 KT 90 MPH 48H 23/0600Z 13.0N 116.3W 80 KT 90 MPH 72H 24/0600Z 14.3N 120.0W 70 KT 80 MPH 96H 25/0600Z 15.2N 123.3W 55 KT 65 MPH 120H 26/0600Z 15.9N 126.0W 40 KT 45 MPH $$ FORECASTER STEWART