Tropical Storm MICHAEL
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TROPICAL STORM MICHAEL DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL132012
500 PM AST TUE SEP 04 2012
MICHAEL HAS BECOME BETTER ORGANIZED DURING THE DAY. ALTHOUGH
GEOSTATIONARY SATELLITE IMAGES INDICATE SOME WARMING OF THE CLOUD
TOPS DURING THE PAST HOUR OR SO...RECENT MICROWAVE DATA INDICATE
THAT A CURVED BAND NOW WRAPS ABOUT THREE-QUARTERS OF THE WAY AROUND
THE CENTER. THE INITIAL WIND SPEED IS SET AT 45 KT...BASED ON
DVORAK CLASSIFICATIONS FROM BOTH TAFB AND SAB AND DATA FROM AN
EARLIER PARTIAL ASCAT PASS THAT SHOWED A COUPLE OF 35 TO 40 KT WIND
VECTORS JUST NORTHWEST OF THE CENTER. ONLY SLIGHT ADDITIONAL
STRENGTHENING IS FORECAST IN THE SHORT TERM AS WESTERLY SHEAR IS
EXPECTED TO INCREASE OVER THE SMALL CYCLONE DURING THE NEXT DAY OR
TWO. AFTER THAT TIME...HOWEVER...AN UPPER-LEVEL LOW IS EXPECTED TO
CUT OFF TO THE SOUTHWEST OF MICHAEL. AS THAT OCCURS...A NARROW
RIDGE IS EXPECTED TO BUILD OVER THE CYCLONE...RESULTING IN A
REDUCTION OF VERTICAL SHEAR. THE OFFICIAL INTENSITY FORECAST IS
INCREASED FROM THE PREVIOUS ADVISORY AND LIES FAIRLY CLOSE TO...BUT
A LITTLE LOWER THAN...THE SHIPS AND LGEM GUIDANCE.
MICHAEL IS MOVING SLOWLY NORTH-NORTHWESTWARD...BUT IS EXPECTED TO
TURN TOWARD THE NORTHEAST IN A DAY OR SO AS A MID-LATITUDE TROUGH
MOVES EASTWARD ACROSS THE CENTRAL ATLANTIC. AFTER THIS TOUGH
BYPASSES MICHAEL...A RIDGE IS FORECAST TO BUILD OVER THE CENTRAL
ATLANTIC TO THE NORTH OF THE CYCLONE. AS THE RIDGE SLIDES
EASTWARD IN A FEW DAYS...IT SHOULD CAUSE MICHAEL TO TURN
NORTHWESTWARD. THE TRACK GUIDANCE IS IN GENERAL AGREEMENT ON
THIS SCENARIO AND THE OFFICIAL FORECAST LIES BETWEEN THE MODEL
CONSENSUS AND THE PREVIOUS NHC TRACK.
FORECAST POSITIONS AND MAX WINDS
INIT 04/2100Z 27.5N 43.7W 45 KT 50 MPH
12H 05/0600Z 28.1N 43.9W 50 KT 60 MPH
24H 05/1800Z 28.8N 43.8W 50 KT 60 MPH
36H 06/0600Z 29.4N 43.3W 50 KT 60 MPH
48H 06/1800Z 29.9N 42.9W 50 KT 60 MPH
72H 07/1800Z 30.9N 43.2W 55 KT 65 MPH
96H 08/1800Z 32.0N 44.0W 60 KT 70 MPH
120H 09/1800Z 33.5N 46.0W 60 KT 70 MPH
$$
FORECASTER BROWN
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