000 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