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| #541883 (Received by flhurricane at: 4:47 PM 10.Sep.2012) TCDAT3 HURRICANE MICHAEL DISCUSSION NUMBER 31 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012 500 PM AST MON SEP 10 2012 THE EYE OF MICHAEL HAS BECOME OBSCURED AND MORE RAGGED DURING THE PAST SEVERAL HOURS. NORTHERLY SHEAR MAY BE INCREASING AS EVIDENCED BY THE APPROACH OF A CIRRUS CLOUD SHIELD FROM THE WEST ASSOCIATED WITH OUTFLOW OF LESLIE. THE CLOUD PATTERN HAS BECOME MORE ASYMMETRIC AS A RESULT OF THE INCREASE IN SHEAR...WITH THE BULK OF THE CLOUDINESS AND DEEP CONVECTION IN THE SOUTHERN SEMICIRCLE. A BLEND OF THE LATEST DVORAK T- AND CI-NUMBERS...AS WELL AS RECENT ADT CI VALUES...SUGGESTS THAT MICHAEL HAS WEAKENED. THE INITIAL INTENSITY ESTIMATE IS LOWERED TO 65 KT...IN LINE WITH THESE DATA. NORTH-NORTHEASTERLY SHEAR AND DECREASING SEA SURFACE TEMPERATURES ARE EXPECTED TO TAKE A TOLL ON MICHAEL DURING THE NEXT 24 TO 36 HOURS. AS A RESULT...CONTINUED WEAKENING IS LIKELY PRIOR TO THE CYCLONE BECOMING A FRONTAL WAVE JUST BEFORE 48 HOURS. POST-TROPICAL MICHAEL IS FORECAST TO BE ABSORBED BY A FRONTAL SYSTEM BY 72 HOURS. THE NHC INTENSITY FORECAST IS REDUCED SLIGHTLY FROM THE PREVIOUS ONE AND IS WEIGHTED TOWARD THE BETTER PERFORMING INTENSITY CONSENSUS AIDS. THE HEADING OF MICHAEL HAS BEGUN TO QUICKLY SHIFT TOWARD THE RIGHT AND THE FORWARD SPEED HAS INCREASED SINCE THE LAST ADVISORY. BASED ON THE RECENT CENTER FIXES...THE INITIAL MOTION ESTIMATE IS 305/10. MICHAEL IS ROUNDING THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL HIGH CENTERED NEAR 39N 45W...AND A TURN TOWARD THE NORTH-NORTHWEST AND THEN THE NORTH WITH A FURTHER INCREASE IN FORWARD SPEED SHOULD OCCUR WITHIN 24 HOURS. AN ACCELERATION TOWARD THE NORTH-NORTHEAST IS EXPECTED AFTER THAT AS MICHAEL BECOMES EMBEDDED IN A FAST-PACED FLOW IN BETWEEN THE RIDGE TO ITS EAST AND A RAPIDLY ADVANCING SHORTWAVE OVER THE CANADIAN MARITIMES. THE NHC TRACK FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE AND LIES IN BETWEEN THE GFS AND ECMWF MODELS...VERY NEAR THE MULTI-MODEL TVCA CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 34.4N 47.6W 65 KT 75 MPH 12H 11/0600Z 36.2N 48.3W 55 KT 65 MPH 24H 11/1800Z 39.8N 47.7W 45 KT 50 MPH 36H 12/0600Z 44.2N 44.8W 40 KT 45 MPH 48H 12/1800Z 49.6N 38.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 13/1800Z...ABOSORBED BY A FRONT $$ FORECASTER KIMBERLAIN |
