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#540361 (Received by flhurricane at: 10:41 AM 05.Sep.2012) TCDAT3 TROPICAL STORM MICHAEL DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012 1100 AM AST WED SEP 05 2012 CONVENTIONAL SATELLITE IMAGERY AND A 1102 UTC SSMIS MICROWAVE OVERPASS INDICATES THAT THE CLOUD PATTERN OF MICHAEL HAS BECOME A LITTLE BETTER ORGANIZED THIS MORNING. THE IMAGERY DEPICTS A BIT LESS OF A SOUTHWEST TO NORTHEAST TILT WITH HEIGHT...AND IMPROVED CURVE BANDING OVER THE NORTHEAST QUADRANT. HOWEVER...DVORAK SATELLITE INTENSITY CLASSIFICATIONS AND A 0800 UTC UW-CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE SUPPORTS HOLDING THE INITIAL INTENSITY AT 45 KT...AT LEAST FOR THIS ADVISORY. MODERATE WEST-NORTHWESTERLY SHEAR CONTINUES TO IMPINGE ON THE WESTERN PORTION OF THE SYSTEM...BUT THE SHEAR IS EXPECTED TO DIMINISH IN A COUPLE OF DAYS. HENCE...STRENGTHENING TO A LOW-END HURRICANE IS FORECAST AT THAT TIME. THROUGH THE REMAINDER OF THE PERIOD...LITTLE CHANGE IN STRENGTH IS REFLECTED IN THE INTENSITY FORECAST...AND IT IS BASED ON THE IVCN MODEL CONSENSUS. MICHAEL HAS MADE A TURN TOWARD THE NORTHEAST IN RESPONSE TO A MAJOR SHORTWAVE TROUGH PASSING TO THE NORTH OF THE CYCLONE...AND THE INITIAL MOTION ESTIMATE IS 035/05. THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH THE 36 PERIOD. AFTERWARD...A RATHER ABRUPT TURN TOWARD THE NORTHWEST IS FORECAST AS THE SUBTROPICAL RIDGE QUICKLY BUILDS IN NORTH OF MICHAEL. THE GLOBAL MODELS ARE IN AGREEMENT WITH A SLOW NORTHWESTWARD MOTION PERSISTING THROUGH DAY 5. THE OFFICIAL FORECAST IS JUST TO THE RIGHT OF THE PREVIOUS TRACK FORECAST...AND SPLITS THE SEAM BETWEEN THE ECMWF AND GFS MODELS. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 28.3N 43.3W 45 KT 50 MPH 12H 06/0000Z 29.0N 43.0W 50 KT 60 MPH 24H 06/1200Z 29.7N 42.4W 50 KT 60 MPH 36H 07/0000Z 30.3N 42.3W 60 KT 70 MPH 48H 07/1200Z 31.0N 42.9W 65 KT 75 MPH 72H 08/1200Z 32.1N 44.2W 70 KT 80 MPH 96H 09/1200Z 33.3N 45.2W 70 KT 80 MPH 120H 10/1200Z 34.7N 46.3W 65 KT 75 MPH $$ FORECASTER ROBERTS |