000 WTPZ43 KNHC 060840 TCDEP3 HURRICANE HENRIETTE DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082013 200 AM PDT TUE AUG 06 2013 AFTER A BRIEF CONVECTIVE RESPITE...A PRONOUNCED CDO FEATURE WITH CLOUD TOPS OF -75C TO -80C HAS DEVELOPED OVER THE CENTER DURING THE PAST 4 HOURS. VARIOUS MICROWAVE DATA DURING THE PAST 6 HOURS INDICATE THAT A WELL-DEFINED AND VERTICALLY ALIGNED EYE HAS DEVELOPED THROUGH A DEEP LAYER OF THE TROPICAL CYCLONE...AND WAS EVEN BRIEFLY EVIDENT IN NIGHT TIME VISIBLE IMAGERY AROUND 0500 UTC. SATELLITE INTENSITY ESTIMATES ARE T4.4/75 KT FROM UW-CIMSS ADT... AND T4.0.65 KT FROM BOTH TAFB AND SAB. THEREFORE...HENRIETTE IS UPGRADED TO A 65-KT HURRICANE...WHICH COULD BE CONSERVATIVE. MICROWAVE SATELLITE IMAGERY INDICATES HENRIETTE HAS WOBBLED TOWARD THE WEST-NORTHWEST DURING THE PAST 6 HOURS. HOWEVER...THIS IS BELIEVED TO BE A TEMPORARY MOTION DUE TO RE-ORGANIZATION OF THE INNER CORE AND DEVELOPMENT OF THE EYE....AND HENRIETTE IS EXPECTED TO RESUME A NORTHWESTWARD MOTION LATER TODAY AS IT MOVES TOWARD A WEAKNESS IN THE MID-PACIFIC SUBTROPICAL RIDGE LOCATED ALONG 136-137W LONGITUDE. BY 48-72 HOURS...THE RIDGE IS FORECAST TO BUILD BACK WESTWARD AS THE UPPER-LEVEL TROUGH INDUCING THE WEAKNESS LIFTS OUT TO THE NORTHEAST. AS THE RIDGE BUILDS WESTWARD...HENRIETTE IS EXPECTED TO TURN WESTWARD OR EVEN WEST-SOUTHWESTWARD ON DAYS 4/5. THE FORECAST TRACK IS CLOSE TO BOTH THE PREVIOUS ADVISORY TRACK AND IS SIMILAR TO THE CONSENSUS MODEL TVCE. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR ADDITIONAL STRENGTHENING TO OCCUR FOR AT LEAST THE NEXT 24 HOURS OR SO...ESPECIALLY GIVEN THE VERY LOW VERTICAL WIND SHEAR CONDITIONS AND IMPRESSIVE OUTFLOW PATTERN. HOWEVER...NONE OF THE RELIABLE MODEL GUIDANCE BRINGS HENRIETTE MUCH ABOVE 75 KT...INCLUDING THE SHIPS AND LGEM MODELS. THESE LOWER INTENSITY VALUES MAY BE THE RESULT OF THOSE MODELS USING SST VALUES THAT ARE ABOUT 0.5C LOWER THAN WHAT IS NOTED IN THE MOST RECENT SST ANALYSES. GIVEN THE 20-25 NMI DIAMETER EYE NOTED IN A RECENT 0555Z AMSU MICROWAVE OVERPASS...THE INTENSITY IS FORECAST TO INCREASE FOR THE NEXT 12-24 HOURS. BY 36 HOURS... GRADUAL WEAKENING IS EXPECTED TO BEGIN AS HENRIETTE MOVES OVER OR NEAR SUB-26C SSTS AND INTO A SLIGHTLY MORE STABLE AIRMASS. HOWEVER...THE WEAKENING MIGHT NOT OCCUR AS QUICKLY OR AS MUCH AS FORECAST DUE TO THE VERY LOW SHEAR CONDITIONS THAT ARE EXPECTED TO EXIST THROUGHOUT THE ENTIRE FORECAST PERIOD. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...AND CLOSELY FOLLOWS THE SHIPS AND LGEM MODELS. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 13.8N 130.9W 65 KT 75 MPH 12H 06/1800Z 14.7N 132.1W 75 KT 85 MPH 24H 07/0600Z 15.8N 133.7W 75 KT 85 MPH 36H 07/1800Z 16.7N 135.3W 70 KT 80 MPH 48H 08/0600Z 17.3N 137.0W 65 KT 75 MPH 72H 09/0600Z 17.8N 141.1W 55 KT 65 MPH 96H 10/0600Z 17.0N 145.3W 40 KT 45 MPH 120H 11/0600Z 16.8N 150.3W 30 KT 35 MPH $$ FORECASTER STEWART