000 WTNT44 KNHC 101458 TCDAT4 TROPICAL STORM MARIA DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011 1100 AM AST SAT SEP 10 2011 MARIA HAS BECOME SIGNIFICANTLY LESS ORGANIZED DURING THE LAST 12-18 HOURS. THE LARGE UPPER-LEVEL LOW AND TROUGH LOCATED NORTH OF PUERTO RICO IS PRODUCING MODERATE WEST TO NORTHWESTERLY SHEAR OVER THE CYCLONE. SATELLITE IMAGERY...SURFACE OBSERVATIONS...AND DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT THE WEAK CIRCULATION CENTER IS APPROACHING ANTIGUA. THE CIRCULATION IS NOT VERY WELL DEFINED...BUT HAS ENOUGH DEFINITION TO MAINTAIN ADVISORIES FOR NOW. THE INITIAL INTENSITY IS GENEROUSLY KEPT AT 35 KT...WITH THE ASSUMPTION THAT TROPICAL-STORM-FORCE WINDS ARE OCCURRING IN THE CONVECTION WELL TO THE NORTHEAST OF THE CENTER. BECAUSE THESE WINDS ARE SO FAR REMOVED FROM THE CENTER...AND NOT EXPECTED TO IMPACT THE LESSER ANTILLES...ALL TROPICAL STORM WARNINGS HAVE BEEN DISCONTINUED. MODEL GUIDANCE SUGGESTS THAT SHEAR WILL CONTINUE OVER THE CYCLONE DURING THE NEXT COUPLE OF DAYS. THE NEW INTENSITY FORECAST THEREFORE CALLS FOR CONTINUED WEAKENING DURING THE NEXT DAY OR TWO. IF MARIA SURVIVES AS A TROPICAL CYCLONE...THE UPPER-LEVEL ENVIRONMENT COULD BECOME A LITTLE MORE FAVORABLE WHEN IT IS FORECAST TO BE EAST OF THE BAHAMAS. THE OFFICIAL FORECAST REFLECTS RESTRENGTHENING...BUT GIVEN THE CURRENT LACK OF STRUCTURE OF THE CYCLONE...IS MUCH LOWER THAN THE OBJECTIVE GUIDANCE. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON A NORTHWESTWARD MOTION DURING THE NEXT COUPLE OF DAYS AROUND THE WESTERN SIDE OF THE SUBTROPICAL RIDGE. A TROUGH MOVING ACROSS THE SOUTHEASTERN UNITED STATES IN 2-3 DAYS IS FORECAST TO TURN MARIA NORTHWARD...THEN NORTH-NORTHEASTWARD LATER IN THE FORECAST PERIOD. THE NEW TRACK FORECAST IS A LITTLE TO THE RIGHT OF THE PREVIOUS ADVISORY DURING THE FIRST COUPLE OF DAYS...BUT THE REMAINDER OF THE TRACK IS ESSENTIALLY AN UPDATE OF THE PREVIOUS NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 17.3N 61.5W 35 KT 40 MPH 12H 11/0000Z 18.4N 63.2W 30 KT 35 MPH 24H 11/1200Z 19.9N 64.9W 30 KT 35 MPH 36H 12/0000Z 21.4N 66.5W 30 KT 35 MPH 48H 12/1200Z 22.7N 68.0W 35 KT 40 MPH 72H 13/1200Z 24.9N 70.2W 45 KT 50 MPH 96H 14/1200Z 29.0N 71.0W 55 KT 65 MPH 120H 15/1200Z 36.0N 68.0W 55 KT 65 MPH $$ FORECASTER BROWN/FRANKLIN