071 
 WTNT44 KNHC 140842
 TCDAT4
  
 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