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| #540232 (Received by flhurricane at: 10:41 PM 04.Sep.2012) TCDAT3 TROPICAL STORM MICHAEL DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012 1100 PM AST TUE SEP 04 2012 THE SATELLITE PRESENTATION OF THE STORM HAS NOT CHANGED MUCH SINCE THE PREVIOUS ADVISORY...EXCEPT FOR A SLIGHT INCREASE IN CENTRAL CONVECTION. DVORAK SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB REMAIN AT 45 KT...SO THE CURRENT INTENSITY IS HELD AT THAT VALUE. WESTERLY SHEAR OVER MICHAEL IS PREDICTED TO STAY MODERATE TO STRONG FOR THE NEXT DAY OR SO...WHICH SHOULD PREVENT SIGNIFICANT STRENGTHENING IN THE SHORT TERM. LATER IN THE FORECAST PERIOD...THE GLOBAL MODELS SHOW AN UPPER-LEVEL LOW CUTTING OFF AND MOVING TO THE SOUTHWEST OF THE TROPICAL CYCLONE. THIS COULD RESULT IN DECREASING SHEAR AND AN ENVIRONMENT MORE CONDUCIVE FOR STRENGTHENING. THE OFFICIAL WIND SPEED FORECAST IS CLOSE TO THE LATEST LGEM GUIDANCE AND THE INTENSITY MODEL CONSENSUS. MICHAEL IS NEAR A COL REGION BETWEEN TWO ANTICYCLONES IN THE MID-LEVEL FLOW... AND HAS MOVED VERY LITTLE SINCE THE LAST ADVISORY. THE STORM SHOULD BEGIN TO MOVE SLOWLY NORTHWARD TO NORTHEASTWARD DURING THE NEXT COUPLE OF DAYS DUE TO A SHORTWAVE TROUGH TO THE NORTH. THIS TROUGH IS FORECAST TO MOVE OUT OF THE AREA IN 48-72 HOURS...HOWEVER...WITH AN ANTICYCLONE DEVELOPING TO THE NORTHWEST OF MICHAEL THERAFTER. THESE CHANGES IN THE STEERING CURRENTS SHOULD CAUSE THE TROPICAL CYCLONE TO TURN TOWARD THE LEFT LATER IN THE FORECAST PERIOD...AND MICHAEL IS EXPECTED TO EVENTUALLY MOVE AROUND THE EASTWARD-MOVING ANTICYCLONE. THE OFFICIAL TRACK FORECAST IS FAIRLY SIMILAR TO THE PREVIOUS ONE AND LIES BETWEEN THE ECMWF AND THE GFS SOLUTIONS. DATA FROM A RECENT ASCAT OVERPASS CONFIRM THAT MICHAEL IS A VERY SMALL TROPICAL STORM. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 27.4N 43.7W 45 KT 50 MPH 12H 05/1200Z 28.1N 43.9W 50 KT 60 MPH 24H 06/0000Z 28.9N 43.5W 50 KT 60 MPH 36H 06/1200Z 29.6N 42.8W 50 KT 60 MPH 48H 07/0000Z 30.0N 42.5W 55 KT 65 MPH 72H 08/0000Z 31.2N 43.0W 60 KT 70 MPH 96H 09/0000Z 32.0N 44.0W 65 KT 75 MPH 120H 10/0000Z 33.0N 45.5W 65 KT 75 MPH $$ FORECASTER PASCH |
