TROPICAL STORM MICHAEL DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL132012
1100 AM AST TUE SEP 04 2012


THE CLOUD PATTERN HAS BECOME A LITTLE BETTER ORGANIZED WITH AN AREA
OF CONCENTRATED DEEP ORGANIZED CONVECTION NEAR THE CENTER. THE
UPPER-LEVEL OUTFLOW...HOWEVER...EXISTS ONLY ON THE EASTERN
SEMICIRCLE AT THIS TIME. SATELLITE INTENSITY ESTIMATES FROM TAFB...
SAB AND CIMSS ARE 2.5 ON THE DVORAK SCALE...SUGGESTING AN INITIAL
INTENSITY OF 35 KNOTS.  THE DEPRESSION IS NOW TROPICAL STORM
MICHAEL...THE 13TH NAMED STORM OF THE 2012 SEASON. ONLY 2005 AND
2011 HAD THE 13TH NAMED STORM FORM EARLIER THAN 4 SEPTEMBER.

MICHAEL IS A VERY SMALL TROPICAL CYCLONE AND IT IS EMBEDDED WITHIN
AN ENVIRONMENT NOT TOO CONDUCIVE FOR SIGNIFICANT INTENSIFICATION.
IN FACT...ONLY A SMALL INCREASE IN THE SHEAR COULD LEAD TO
WEAKENING. IF MICHAEL SURVIVES A COUPLE OF DAYS...THERE IS AN
OPPORTUNITY FOR SLIGHT STRENGTHENING AS AN UPPER-LOW FORMS SOUTH OF
THE CYCLONE RESULTING IN A LESS HOSTILE UPPER-LEVEL ENVIRONMENT.
THE NHC FORECAST CALLS FOR NOT MUCH CHANGE IN INTENSITY AND ALLOWS
SLIGHT INTENSIFICATION BY THE LATTER PART OF THE FORECAST...BUT NOT
AS HIGH AS INDICATED BY THE STATISTICAL INTENSITY MODELS.

MICHAEL IS MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 4
KNOTS...EMBEDDED WITHIN LIGHT SOUTHERLY STEERING CURRENTS WEST OF
THE SUBTROPICAL RIDGE.  GLOBAL MODELS ARE FORECASTING A SHORT WAVE
TROUGH TO BYPASS MICHAEL...LEAVING THE STORM WITHIN A WEAK STEERING
FLOW. THIS PATTERN SHOULD KEEP MICHAEL MEANDERING BETWEEN THE
NORTH-NORTHWEST AND NORTHWARD THROUGH FIVE DAYS. ALTHOUGH THE
GUIDANCE IS NOT IN GOOD AGREEMENT...PRIMARILY IN SPEED...MOST OF
THE MODELS MOVE MICHAEL ON A GENERAL NORTHWARD TREND. THE NHC
FORECAST IS IN BETWEEN THE GFS AND THE ECMWF.


FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 27.0N  43.5W   35 KT  40 MPH
12H  05/0000Z 27.7N  44.0W   35 KT  40 MPH
24H  05/1200Z 28.5N  44.2W   35 KT  40 MPH
36H  06/0000Z 29.0N  44.0W   35 KT  40 MPH
48H  06/1200Z 29.5N  43.5W   35 KT  40 MPH
72H  07/1200Z 30.5N  43.4W   40 KT  45 MPH
96H  08/1200Z 31.5N  43.5W   40 KT  45 MPH
120H  09/1200Z 33.0N  44.5W   35 KT  40 MPH

$$
FORECASTER AVILA