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| #541636 (Received by flhurricane at: 4:35 PM 09.Sep.2012) TCDAT3 HURRICANE MICHAEL DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012 500 PM AST SUN SEP 09 2012 THE MIXING EVENT ACTIVE WITHIN THE INNER CORE OF MICHAEL APPEARS TO BE NEAR COMPLETION....AND A TRANSFORMATION HAS TAKEN PLACE. THE EYE OF THE CYCLONE HAS BECOME MORE RAGGED AND CLOUD- FILLED SINCE THIS MORNING...WITH ITS DIAMETER MEASURING 30 N MI AFTER BEING AROUND 10 N MI ABOUT 12 HOURS AGO. THE CLOUD PATTERN IS NO LONGER SYMMETRIC...AND CLOUD TOP TEMPERATURES CONTINUE TO WARM. DVORAK T-NUMBERS ARE UNCHANGED AT 4.5 FROM TAFB AND SAB...AND THE ADT CI VALUE IS 5.2. THE INITIAL INTENSITY IS KEPT AT 80 KT IN AGREEMENT WITH A BLEND OF THESE DATA. MICHAEL HAS BEEN MOVING DUE WEST SINCE THIS MORNING...AND HAS EVEN WOBBLED A BIT SOUTH OF WEST IN RECENT HOURS. THE INITIAL MOTION ESTIMATE...A LONGER-TERM AVERAGE...IS 270/04. SOUTH OF A SMALL MID-LEVEL RIDGE...MICHAEL SHOULD CONTINUE ON A SLOW WESTWARD TO WEST-NORTHWESTWARD COURSE FOR THE NEXT 24 HOURS. THE CYCLONE SHOULD REACH THE WESTERN PERIPHERY OF THIS RIDGE AROUND THAT TIME AND TURN NORTHWESTWARD. A TURN TOWARD THE NORTH AND THEN NORTH-NORTHEAST WITH A SIGNIFICANT INCREASE IN FORWARD SPEED IS EXPECTED IN 36-72 HOURS...AS THE SAME SHORTWAVE TROUGH CAUSING LESLIE TO RECURVE APPROACHES MICHAEL. THE NHC TRACK FORECAST HAS AGAIN BEEN ADJUSTED A BIT TO THE LEFT THROUGH 48 HOURS...FOLLOWING THE MULTI-MODEL CONSENSUS...AND TO THE RIGHT AT 72 HOURS IN BEST AGREEMENT WITH THE GFS MODEL. MICHAEL SHOULD LEAVE THE LOW-SHEAR ENVIRONMENT SOUTH OF THE AFOREMENTIONED RIDGE AND BEGIN TO FEEL THE EFFECTS OF MODERATE TO STRONG NORTH-NORTHEASTERLY SHEAR ASSOCIATED WITH THE OUTFLOW OF LESLIE. SINCE THE SHEAR IS FORECAST TO BE ONLY OVER A NARROW LAYER IN THE UPPER TROPOSPHERE...AND MICHAEL WILL BE MOVING OVER ONLY GRADUALLY DECREASING SEA SURFACE TEMPERATURES...ONLY SLOW WEAKENING IS FORECAST DURING THE NEXT DAY OR SO. FASTER WEAKENING IS FORECAST BY 48 HOURS HOURS ONCE MICHAEL ENCOUNTERS A SUBSTANTIAL INCREASE IN SOUTH-SOUTHWESTERLY SHEAR ASSOCIATED WITH A STRONG SHORTWAVE TROUGH CROSSING THE CANADIAN MARITIMES. THE NHC INTENSITY FORECAST IS REDUCED SLIGHTLY FROM THE PREVIOUS ONE AND IS EXCELLENT AGREEMENT WITH THE LATEST SHIPS AND INTENSITY CONSENSUS AIDS. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 33.6N 43.8W 80 KT 90 MPH 12H 10/0600Z 33.6N 44.9W 75 KT 85 MPH 24H 10/1800Z 34.2N 46.6W 70 KT 80 MPH 36H 11/0600Z 36.4N 47.8W 65 KT 75 MPH 48H 11/1800Z 39.9N 47.5W 50 KT 60 MPH 72H 12/1800Z 47.2N 40.9W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 13/1800Z...DISSIPATED $$ FORECASTER KIMBERLAIN |
