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| #541821 (Received by flhurricane at: 10:53 AM 10.Sep.2012) TCDAT3 HURRICANE MICHAEL DISCUSSION NUMBER 30 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012 1100 AM AST MON SEP 10 2012 THE SATELLITE PRESENTATION OF MICHAEL HAS NOT CHANGED MUCH IN ORGANIZATION SINCE THE LAST ADVISORY. WHILE THE EYE HAS CLEARED AND BECOME SOMEWHAT BETTER DEFINED...CLOUD TOP TEMPERATURES HAVE NOT COOLED APPRECIABLY. THE CLOUD PATTERN HAS RECENTLY BECOME MORE SYMMETRIC...BUT THERE IS STILL EVIDENCE OF NORTHERLY SHEAR OVER THE CYCLONE. SINCE DVORAK T-NUMBERS FROM TAFB/SAB ARE UNCHANGED SINCE 0600 UTC...THE INITIAL INTENSITY ESTIMATE IS HELD AT 70 KT. WEAKENING SHOULD BEGIN IN EARNEST AS MICHAEL ENCOUNTERS INCREASING NORTH-NORTHEASTERLY SHEAR AND SLOWLY DECREASING SEA SURFACE TEMPERATURES DURING THE NEXT 24-36 HOURS. AFTER THAT...EVEN COOLER WATERS AND STRONG SOUTH-SOUTHWESTERLY SHEAR SHOULD HASTEN THE TRANSITION OF MICHAEL TO AN EXTRATROPICAL CYCLONE IN ABOUT 48 HOURS. THE NHC INTENSITY FORECAST IS JUST A BIT LOWER THAN THE PREVIOUS ONE...IN GOOD AGREEMENT WITH THE LATEST SHIPS OUTPUT AS WELL AS THE INTENSITY CONSENSUS AIDS. MICHAEL HAS BEEN MOVING SLIGHTLY FASTER TOWARD THE WEST...THOUGH RECENT CENTER FIXES SUGGEST A MOTION TO THE RIGHT OF THAT HEADING NOW. THE INITIAL MOTION ESTIMATE...REPRESENTING A LONGER-TERM AVERAGE OF CENTER FIXES...IS 270/07. THE CYCLONE SHOULD BE STEERED WEST-NORTHWESTWARD AND THEN NORTHWESTWARD DURING THE NEXT 12-18 HOURS AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE NEAR 38N 46W. BEYOND THIS TIME...A TURN TOWARD THE NORTH AND THEN NORTH-NORTHEAST WITH SIGNIFICANT ACCELERATION IS EXPECTED. THIS SHOULD OCCUR AS MICHAEL BECOMES EMBEDDED IN THE FLOW BETWEEN THE RIDGE TO ITS EAST AND A POTENT SHORTWAVE TROUGH MOVING THROUGH THE CANADIAN MARITIMES. WITH THE TRACK GUIDANCE IN RELATIVELY GOOD AGREEMENT...NO SIGNIFICANT CHANGES WERE MADE TO THE PREVIOUS FORECAST TRACK. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 33.6N 46.3W 70 KT 80 MPH 12H 11/0000Z 34.8N 47.6W 60 KT 70 MPH 24H 11/1200Z 37.5N 48.1W 50 KT 60 MPH 36H 12/0000Z 41.2N 46.7W 45 KT 50 MPH 48H 12/1200Z 45.9N 42.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 13/1200Z 54.0N 28.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 14/1200Z...ABSORBED BY FRONT $$ FORECASTER KIMBERLAIN |
