[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 160248
TCDAT4

HURRICANE MARIA DISCUSSION NUMBER  38
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
1100 PM AST THU SEP 15 2011

SATELLITE IMAGERY INDICATES DEEP CONVECTION HAS BECOME MORE
CONCENTRATED NEAR THE CENTER OF MARIA...ALTHOUGH TOPS HAVE WARMED A
LITTLE DURING THE PAST COUPLE OF HOURS. ALSO...A 30 NMI DIAMETER
EYE HAS BEEN APPARENT IN EARLIER MICROWAVE SATELLITE IMAGERY. THE
INITIAL INTENSITY HAS BEEN INCREASED TO 70 KT BASED ON A SATELLITE
INTENSITY ESTIMATE OF T4.5/77 KT FROM TAFB...THE EYE FEATURE NOTED
IN MICROWAVE IMAGERY...AND THE FASTER FORWARD SPEED OF MARIA.

MARIA CONTINUES TO ACCELERATE AND THE MOTION ESTIMATE IS NOW 035/37
KT. THE CYCLONE SHOULD GRADUALLY TURN TOWARD THE NORTHEAST AND
CONTINUE TO ACCELERATE AHEAD OF AN EASTWARD-MOVING DEEP-LAYER
TROUGH AND FRONTAL SYSTEM THAT EXTENDS FROM NOVA SCOTIA
SOUTHWESTWARD TO THE OUTER BANKS OF NORTH CAROLINA. THE GLOBAL AND
REGIONAL MODELS ARE IN EXCELLENT AGREEMENT ON MARIA PASSING OVER OR
NEAR THE AVALON PENINSULA OF SOUTHEASTERN NEWFOUNDLAND IN ABOUT 18
HOURS. AS A RESULT...THE OFFICIAL FORECAST HAS ONLY BEEN NUDGED
SLIGHTLY TO THE WEST OF THE PREVIOUS TRACK...AND IS NOW IN THE
MIDDLE OF THE GUIDANCE ENVELOPE AND CLOSE TO THE CONSENSUS SPEED OF
THE GFS...UKMET...AND ECMWF MODELS.

SINCE MARIA IS NOW RAPIDLY APPROACHING A SHARP SST GRADIENT THAT
LIES ALONG 40N LATITUDE...LITTLE CHANGE IN STRENGTH IS EXPECTED
UNTIL THE CYCLONE REACHES THE AVALON PENINSULA. ALTHOUGH CONVECTION
MAY WANE AFTER MARIA MOVES OVER COLDER WATER NORTH OF 40N...THE
FASTER FORWARD SPEED OF 45-50 KT SHOULD HELP TO OFFSET ANY LOSS OF
CONVECTIVE ORGANIZATION. THE OFFICIAL INTENSITY FORECAST IS SIMILAR
TO THE PREVIOUS ADVISORY AND THE LGEM INTENSITY MODEL.

EXTRATROPICAL TRANSITION AND FORECAST POINTS WERE COORDINATED WITH
THE NOAA OCEAN PREDICTION CENTER AND THE CANADIAN HURRICANE CENTRE.

FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 38.5N  63.5W   70 KT  80 MPH
 12H  16/1200Z 43.3N  58.6W   70 KT  80 MPH
 24H  17/0000Z 50.7N  50.6W   60 KT  70 MPH...POST-TROP/EXTRATROP
 36H  17/1200Z 58.0N  45.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  18/0000Z...ABSORBED BY LARGER EXTRATROPICAL LOW

$$
FORECASTER STEWART



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