Tropical Storm MARIA

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TROPICAL STORM MARIA DISCUSSION NUMBER  30
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
1100 PM AST TUE SEP 13 2011
 
ALTHOUGH IT APPEARS THAT THE SHEAR OVER MARIA HAS AT LEAST
TEMPORARILY ABATED...THE OVERALL ORGANIZATION OF THE CLOUD PATTERN
HAS NOT IMPROVED SIGNIFICANTLY.  THE LOW-LEVEL CENTER IS BELIEVED
TO BE LOCATED NEAR THE NORTHWESTERN EDGE OF THE MAIN MASS OF DEEP
CONVECTION.  SATELLITE-BASED INTENSITY ESTIMATES FROM TAFB AND SAB
ARE 55 KT AND 35 KT RESPECTIVELY...AND GIVEN THE LACK OF INCREASED
ORGANIZATION...THE WIND SPEED IS KEPT AT 45 KT FOR THIS ADVISORY.
NUMERICAL GUIDANCE INDICATES THAT THE SHEAR DOES NOT BECOME
PROHIBITIVELY STRONG UNTIL ABOUT 48 HOURS...SO SOME STRENGTHENING
COULD OCCUR PRIOR TO THAT TIME.  THE OFFICIAL INTENSITY FORECAST IS
SIMILAR TO THE LGEM GUIDANCE...AND TO THE PREVIOUS FORECAST.
GLOBAL MODELS DEPICT MARIA BEGINNING TO LOSE TROPICAL CYCLONE
STRUCTURE SOON AFTER 48 HOURS AS IT MERGES WITH A WELL-DEFINED
BAROCLINIC ZONE.  WITHIN 3 TO 4 DAYS...THE SYSTEM IS LIKELY TO
BECOME ABSORBED BY A STRONG MID-LATITUDE LOW PRESSURE SYSTEM OVER
EASTERN CANADA.
 
THE BEST GUESS AT THE INITIAL MOTION IS A RATHER UNCERTAIN 350/8. 
THERE ARE NO IMPORTANT CHANGES TO THE EXPECTED STEERING PATTERN. 
OVER THE NEXT DAY OR SO...MARIA SHOULD MOVE GENERALLY NORTHWARD AT
AN INCREASING FORWARD SPEED ALONG THE WESTERN SIDE OF A SUBTROPICAL
HIGH PRESSURE AREA.  BY 48 HOURS...A STRONG DEEP-LAYER TROUGH
MOVING OVER THE NORTHEASTERN U.S. IS LIKELY TO CAUSE THE STORM TO
TURN TOWARD THE NORTH-NORTHEAST WITH ADDITIONAL ACCELERATION.  THE
TRACK MODEL CONSENSUS HAS SHIFTED A LITTLE TO THE WEST ON THIS
CYCLE...BUT VERY LITTLE ADJUSTMENT HAS BEEN MADE TO THE TRACK
FORECAST FROM THE PREVIOUS ADVISORY.  THE CURRENT NHC TRACK IS
FAIRLY CLOSE TO THE GFS SOLUTION...ALTHOUGH NOT QUITE AS FAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/0300Z 23.5N  68.2W   45 KT  50 MPH
 12H  14/1200Z 25.5N  68.5W   50 KT  60 MPH
 24H  15/0000Z 28.8N  68.7W   50 KT  60 MPH
 36H  15/1200Z 32.8N  67.7W   55 KT  65 MPH
 48H  16/0000Z 38.0N  64.3W   55 KT  65 MPH
 72H  17/0000Z 52.0N  50.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  18/0000Z...ABSORBED
 
$$
FORECASTER PASCH
 
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