000 WTNT44 KNHC 122033 TCDAT4 TROPICAL STORM MARIA DISCUSSION NUMBER 25 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011 500 PM AST MON SEP 12 2011 MARIA HAS BEEN NEARLY STATIONARY FOR MUCH OF THE DAY...HOWEVER A SLOW NORTHWARD OR NORTHWESTWARD MOTION HAS BEEN APPARENT VERY RECENTLY. THE LOW-LEVEL CENTER REMAINS NEAR THE WESTERN EDGE OF A BURST OF NEW CONVECTION THAT HAS DEVELOPED THIS AFTERNOON. NOAA BUOY 41043...LOCATED ABOUT 125 N MI EAST OF THE CENTER...RECENTLY REPORTED A 1-MINUTE SUSTAINED WIND OF 39 KT WITH A GUST TO 45 KT. THIS OBSERVATION ALONG WITH THE 1800 UTC DVORAK ESTIMATES SUPPORT MAINTAINING AN INITIAL INTENSITY OF 45 KT. STRONG SHEAR FROM AN UPPER-LEVEL LOW AND TROUGH TO THE NORTH AND NORTHWEST OF MARIA IS EXPECTED TO CONTINUE DURING THE NEXT DAY OR SO. AFTER THAT... SOUTHWESTERLY UPPER-LEVEL FLOW AHEAD OF A LARGE MID-LATITUDE TROUGH MOVING OFF THE SOUTHEAST UNITED STATES IS EXPECTED TO MAINTAIN MODERATE TO STRONG SHEAR OVER THE SYSTEM. THE NHC INTENSITY FORECAST CALLS FOR LITTLE SIGNIFICANT CHANGE IN STRENGTH DURING THE FORECAST PERIOD...WHICH IS CONSISTENT WITH THE LGEM MODEL. ALTHOUGH MARIA HAS MOVED VERY LITTLE TODAY...THE MODEL GUIDANCE INSISTS THAT THE CYCLONE WILL BEGIN MOVING SLOWLY NORTHWESTWARD AROUND THE WESTERN SIDE OF A LOW- TO MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC. MARIA SHOULD TURN NORTHWARD THEN NORTHEASTWARD AS IT RECURVES AHEAD OF A MID-LATITUDE TROUGH AND FRONT MOVING OFF THE EAST COAST OF THE UNITED STATES DURING THE NEXT FEW DAYS. THE TRACK GUIDANCE IS IN RELATIVELY GOOD AGREEMENT BUT SHOWS A SLOWER MOTION THAN IN PREVIOUS RUNS. THE OFFICIAL TRACK IS SLIGHTLY EAST OF THE PREVIOUS ADVISORY AND NOT AS FAST. THE TROPICAL STORM FORCE WIND RADIUS OVER THE SOUTHEASTERN QUADRANT HAS BEEN EXPANDED BASED ON 1324 UTC ASCAT DATA THAT SHOWED A SMALL AREA OF 30-35 KT WINDS WELL EAST-SOUTHEAST OF THE CENTER. IT IS WORTH REMEMBERING THAT NHC RADII ESTIMATES REPRESENT THE MAXIMUM EXTENT OF A PARTICULAR WIND THRESHOLD ANYWHERE WITHIN A QUADRANT. IN THIS CASE...THE INITIAL WIND FIELD GRAPHIC IS LIKELY TO DEPICT TROPICAL STORM FORCE WINDS NEAR OR OVER THE NORTHERN CARIBBEAN ISLANDS WHEN IT REALITY THEY ARE OCCURRING ONLY OVER WATER IN A SMALL AREA WELL TO EAST-SOUTHEAST OF THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 21.0N 67.5W 45 KT 50 MPH 12H 13/0600Z 21.6N 68.0W 45 KT 50 MPH 24H 13/1800Z 22.8N 68.6W 50 KT 60 MPH 36H 14/0600Z 24.8N 69.2W 50 KT 60 MPH 48H 14/1800Z 27.5N 69.2W 50 KT 60 MPH 72H 15/1800Z 34.5N 67.0W 50 KT 60 MPH 96H 16/1800Z 45.0N 55.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 17/1800Z...DISSIPATED $$ FORECASTER BROWN