000 WTNT44 KNHC 130233 TCDAT4 TROPICAL STORM MARIA DISCUSSION NUMBER 26 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011 1100 PM AST MON SEP 12 2011 ALTHOUGH UNDER THE INFLUENCE OF STRONG SOUTHWESTERLY SHEAR...MARIA CONTINUES TO PRODUCE DEEP CONVECTION WHICH APPEARS TO HAVE RECENTLY DEVELOPED A BIT CLOSER TO THE CENTER. HOWEVER...LAST-LIGHT VISIBLE IMAGES SUGGESTED THAT THE LOW-LEVEL CIRCULATION IS LESS DEFINED AND THE COVERAGE OF COLD CLOUD TOPS IS NOT AS WIDESPREAD AS 24 HOURS AGO. WITH DVORAK T-NUMBERS FROM TAFB AND SAB UNCHANGED AND THE SATELLITE PRESENTATION GENERALLY NO DIFFERENT THAN EARLIER...THE INITIAL INTENSITY IS HELD AT 45 KT. THE PREVAILING WESTERLY SHEAR OVER MARIA IS NOT LIKELY TO DECREASE SUBSTANTIALLY DURING THE NEXT COUPLE OF DAYS WHICH SUGGESTS THAT ANY INTENSIFICATION WILL BE SHORT-LIVED. THE SHEAR IS FORECAST TO INCREASE EVEN FURTHER AFTER ABOUT 60 HOURS...MAKING THE SURVIVAL OF MARIA AS A TROPICAL CYCLONE BEYOND THAT TIME QUESTIONABLE. THE OFFICIAL INTENSITY FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE AND SHOWS LITTLE CHANGE IN STRENGTH DURING THE FORECAST PERIOD. A 96-HOUR FORECAST POINT IS INDICATED...THOUGH THE GUIDANCE IS AMBIGUOUS AS TO WHETHER THE POST-TROPICAL CYCLONE WILL BE A VIABLE ENTITY AT THAT TIME. AN ALTERNATIVE AND EQUALLY PLAUSIBLE SCENARIO WOULD BE FOR MARIA TO SUCCUMB TO THE HIGH SHEAR...BECOME A SHALLOW CYCLONE..AND DISSIPATE. THE POOR DEFINITION OF THE CENTER AND NO RECENT MICROWAVE DATA HAS MADE IT DIFFICULT TO ASSESS THE INITIAL MOTION...BUT IT APPEARS AS IF MARIA HAS BEEN NEARLY STATIONARY OR DRIFTING NORTHWESTWARD. THE STORM HAS TEMPORARILY BEEN TRAPPED IN A WEAK STEERING FLOW BETWEEN MID-LEVEL ANTICYCLONES TO ITS EAST AND WEST. WITHIN ABOUT 24 HOURS...THE STORM IS FORECAST TO BE CAUGHT UP IN A DEEP-LAYER SOUTHERLY FLOW ON THE WEST SIDE OF A CENTRAL ATLANTIC RIDGE. AN ACCELERATION TOWARD THE NORTH-NORTHEAST TO NORTHEAST SHOULD OCCUR IN 48-72 HOURS AHEAD OF A LARGE MID-LATITUDE TROUGH SWINGING THROUGH NEW ENGLAND. THE TRACK GUIDANCE IS RELATIVELY STABLE AND THE SPREAD IS REASONABLY SMALL...MAKING ONLY COSMETIC CHANGES NECESSARY TO THE PREVIOUS NHC TRACK FORECAST. A CREDIBLE 40-KT SHIP REPORT ABOUT 175 N MI EAST-NORTHEAST OF THE CENTER OF MARIA WAS USED TO EXPAND THE WIND RADIUS IN THE NORTHEAST QUADRANT. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 21.3N 67.5W 45 KT 50 MPH 12H 13/1200Z 22.3N 68.1W 45 KT 50 MPH 24H 14/0000Z 24.0N 68.8W 45 KT 50 MPH 36H 14/1200Z 26.3N 69.1W 50 KT 60 MPH 48H 15/0000Z 29.3N 68.8W 50 KT 60 MPH 72H 16/0000Z 37.5N 64.0W 50 KT 60 MPH 96H 17/0000Z 48.5N 50.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 18/0000Z...DISSIPATED $$ FORECASTER KIMBERLAIN