Tropical Storm MARIA

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL STORM MARIA DISCUSSION NUMBER  31
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
500 AM AST WED SEP 14 2011
 
SEVERAL FORTUITOUS OBSERVATIONS FROM NOAA BUOY 41046 WERE USED TO
PLACE THE LOW-LEVEL CENTER OF MARIA JUST WEST OF THE BUOY...AND
JUST INSIDE THE NORTHWESTERN EDGE OF THE DEEP CONVECTIVE CLOUD
MASS. BUOY 41046 HAS BEEN REPORTING NEAR STEADY 35-KT WINDS THE
PAST SEVERAL HOURS WITH A PRESSURE OF 1004.5 MB AT 06Z. BASED ON
THIS INFORMATION...IT IS ASSUMED THAT THE BUOY LIES INSIDE THE
RADIUS OF MAXIMUM WINDS AND THAT THE ESTIMATED CENTRAL PRESSURE OF
MARIA IS NEAR 1001 MB. GIVEN THAT SEVERAL SHIPS AND BUOYS HAVE
REPORTED PRESSURES ABOVE 1015 MB ABOUT 200 NMI NORTHEAST OF THE
CENTER...I FEEL THAT MAXIMUM WINDS OF 50 KT LIE JUST NORTHEAST OF
THE BUOY IN A VERY TIGHT PRESSURE GRADIENT IN THAT QUADRANT. THIS
INTENSITY IS CONSISTENT WITH A TAFB SATELLITE INTENSITY ESTIMATE OF
T3.5/55 KT USING A SHEAR PATTERN...AND ALSO CORRESPONDS TO THE
HIGHER-THAN-STANDARD PRESSURE-WIND RELATIONSHIP NOTED IN AIRCRAFT
RECONNAISSANCE DATA THREE DAYS AGO.

THE INITIAL MOTION ESTIMATE IS 345/09 KT. NHC MODEL GUIDANCE REMAINS
IN EXCELLENT AGREEMENT ON MARIA TURNING NORTHWARD DURING THE NEXT
12 HOURS AS THE CYCLONE ROUNDS THE WESTERN PERIPHERY OF A WEAKENING
SUBTROPICAL RIDGE. BY 24-30 HOURS AS MARIA PASSES WEST OF
BERMUDA...THE TROPICAL STORM IS FORECAST TO RAPIDLY ACCELERATE TO
THE NORTHEAST AHEAD OF A LARGE DEEP-LAYER TROUGH THAT IS CURRENTLY
PUSHING EASTWARD OFF THE U.S. EAST COAST. MARIA IS EXPECTED TO
MERGE WITH A FRONTAL SYSTEM NEAR NEWFOUNDLAND IN 60-72 HOURS...AND
BE ABSORBED BY A LARGER EXTRATROPICAL LOW PRESSURE SYSTEM NORTH OF
THE CANADIAN MARITIMES REGION BY 96 HOURS. THE OFFICIAL FORECAST
TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK...AND REMAINS ALONG
THE EASTERN EDGE OF THE NHC GUIDANCE ENVELOPE.

THE BEST OPPORTUNITY FOR STRENGTHENING TO OCCUR IS WITHIN THE NEXT
24 HOURS OR SO WHEN THE VERTICAL WIND SHEAR IS EXPECTED TO BE THE
LOWEST...AND SSTS AND MID-LEVEL MOISTURE WILL BE THE HIGHEST. BY 48
HOURS...STRONG SOUTHWESTERLY SHEAR AHEAD OF THE AFOREMENTIONED
TROUGH IS EXPECTED TO INCREASE ABOVE 40 KT...WHICH WILL BE
COINCIDENT WITH MARIA MOVING OVER SSTS LESS THAN 20C. THE
COMBINATION OF THESE UNFAVORABLE ENVIRONMENTAL CONDITIONS SHOULD
HALT THE INTENSIFICATION PROCESS AND INDUCE A QUICK TRANSITION TO
AN EXTRATROPICAL CYCLONE BEFORE MERGER WITH A FRONTAL SYSTEM
OCCURS. THE OFFICIAL INTENSITY FORECAST REMAINS CLOSE TO THE LGEM
GUIDANCE...AND IS BELOW THE INTENSITY CONSENSUS MODEL...ICON...
ESPECIALLY AT 48 HOURS AND BEYOND.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/0900Z 24.2N  68.6W   50 KT  60 MPH
 12H  14/1800Z 26.7N  68.8W   55 KT  65 MPH
 24H  15/0600Z 30.4N  68.5W   60 KT  70 MPH
 36H  15/1800Z 35.3N  66.0W   60 KT  70 MPH
 48H  16/0600Z 41.1N  60.7W   55 KT  65 MPH
 72H  17/0600Z 55.8N  45.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  18/0600Z...ABSORBED
 
$$
FORECASTER STEWART
 
NNNN