Tropical Storm MARIA Forecast Discussion Number 36

 | By Seamus on 9/15/2011 12:08:05 PM | Views (67) Issued at 1100 AM AST THU SEP 15 2011

000
WTNT44 KNHC 151441
TCDAT4
 
TROPICAL STORM MARIA DISCUSSION NUMBER  36
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
1100 AM AST THU SEP 15 2011
 
MICROWAVE IMAGES DURING THE PAST SEVERAL HOURS INDICATE THAT MARIA
HAS BECOME BETTER ORGANIZED.  AN EYE...OPEN TO THE SOUTH...IS
APPARENT IN THE LATEST MICROWAVE IMAGES...ALTHOUGH THERE IS STILL
SOME TILT BETWEEN THE LOW AND MID-LEVEL CENTERS.  SUBJECTIVE DVORAK
ESTIMATES ARE 55 KT...WITH CIMSS AMSU ESTIMATES OF 63 KT AND ADT
VALUES OF 57 KT.  THE INITIAL WINDS ARE INCREASED TO 60 KT...AND
MIGHT BE A LITTLE CONSERVATIVE GIVEN THE BETTER DEFINED CORE
FEATURES AND THE FAST FORWARD SPEED.  MARIA HAS ABOUT 24 HOURS OF
WARM WATER AND MODERATE SHEAR BEFORE IT CROSSES THE NORTH WALL OF
THE GULF STREAM AND ENCOUNTERS A MUCH HIGHER SHEAR ENVIRONMENT.  ALL
OF THE GUIDANCE MAKES MARIA A HURRICANE LATER TODAY BEFORE
WEAKENING ON FRIDAY...AND THE OFFICIAL FORECAST AGREES WITH THAT
SCENARIO.

MARIA IS MOVING QUICKLY TO THE NORTH-NORTHEAST AT ABOUT 26 KT. 
GLOBAL MODELS ARE IN RELATIVELY GOOD AGREEMENT ON A TRACK TOWARD
THE NORTHEAST STARTING BY TONIGHT AT A RATE OF ABOUT 40 KT AS THE
CYCLONE BECOMES EMBEDDED IN FAST MID-LATITUDE FLOW.  THERE HAS BEEN
A SUBTLE NORTHWESTWARD SHIFT IN THE GUIDANCE...WITH A FAIR NUMBER
OF THE MODELS BRINGING THE EXTRATROPICAL CYCLONE CLOSE TO THE
AVALON PENINSULA OF NEWFOUNDLAND.  THE LATEST FORECAST IS SHIFTED
TO THE LEFT...BUT STILL REMAINS ON THE SOUTHEASTERN SIDE OF THE
GUIDANCE ENVELOPE.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/1500Z 32.4N  67.0W   60 KT  70 MPH
 12H  16/0000Z 36.7N  64.1W   65 KT  75 MPH
 24H  16/1200Z 42.8N  57.4W   65 KT  75 MPH
 36H  17/0000Z 49.5N  49.5W   55 KT  65 MPH...POST-TROP/EXTRATROP
 48H  17/1200Z...ABSORBED BY A COLD FRONT
 
$$
FORECASTER BLAKE
 

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