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#459763 (Received by flhurricane at: 4:47 AM 16.Sep.2011) TCDAT4 HURRICANE MARIA DISCUSSION NUMBER 39 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011 500 AM AST FRI SEP 16 2011 AN 0540 UTC AMSR-E OVERPASS INDICATES THAT THE EYEWALL OF MARIA IS OPEN IN THE SOUTHWEST QUADRANT AND THAT THE RING OF DEEP CONVECTION IS THINNING. HOWEVER...THE LATEST ADT ESTIMATE IS 72 KT...AND A BLEND OF FINAL-T AND CI NUMBERS FROM TAFB AND SAB YIELDS AN INTENSITY BETWEEN 65 AND 72 KT. THE INITIAL INTENSITY IS THEREFORE MAINTAINED AT 70 KT. MARIA CONTINUES TO ACCELERATE AND NOW HAS AN INITIAL MOTION OF 035/39 KT. THE HURRICANE IS EXPECTED TO CONTINUE ACCELERATING NORTHEASTWARD OVER THE NEXT 24 HOURS AHEAD OF A DEEP-LAYER TROUGH THAT CURRENTLY EXTENDS FROM NORTHERN QUEBEC INTO THE NORTHEASTERN UNITED STATES. THE NEW OFFICIAL TRACK FORECAST IS NEARLY IDENTICAL TO THE PREVIOUS ONE UP UNTIL LANDFALL IN NEWFOUNDLAND...WHICH IS FORECAST TO OCCUR IN 12 HOURS OR SO...AND ONLY DEVIATES SLIGHTLY TO THE NORTHWEST THEREAFTER. THIS SOLUTION IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE. MARIA IS CROSSING THE STRONG SST GRADIENT ON THE NORTH SIDE OF THE GULF STREAM AND IS OVER WATERS OF ABOUT 22-23 DEGREES CELSIUS. THE COLDER WATERS SHOULD INDUCE WEAKENING...BUT SINCE THE HURRICANE IS MOVING SO FAST...IT PROBABLY WILL NOT WEAKEN MUCH BEFORE REACHING NEWFOUNDLAND. A COLD FRONT IS FAST-APPROACHING MARIA FROM THE WEST...AND GLOBAL MODEL FIELDS SUGGEST THAT THE CYCLONE WILL BE ALMOST FULLY EMBEDDED WITHIN THE FRONTAL ZONE NEAR OR JUST AFTER 18 UTC TODAY. THE OFFICIAL INTENSITY FORECAST STILL SHOWS MARIA AS A 65-KT HURRICANE IN 12 HOURS AS IT APPROACHES NEWFOUNDLAND...BUT EXTRATROPICAL TRANSITION SHOULD BE NEARING COMPLETION AT THAT TIME. AS SHOWN BY THE INTENSITY GUIDANCE...THE POST-TROPICAL CYCLONE SHOULD WEAKEN AFTER PASSING NEWFOUNDLAND AND THEN IS EXPECTED TO BECOME ABSORBED WITHIN AN OCCLUDED FRONTAL ZONE BY 36 HOURS. THE INTENSITY AND WIND RADII DURING THE POST-TROPICAL STAGE WERE COORDINATED WITH THE NOAA OCEAN PREDICTION CENTER. THE 12-FT SEAS RADII HAVE BEEN TRIMMED IN THE NORTHERN SEMICIRCLE SINCE MARIA IS OUTRUNNING THE HIGHEST WAVES. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 41.7N 60.3W 70 KT 80 MPH 12H 16/1800Z 46.8N 54.8W 65 KT 75 MPH 24H 17/0600Z 55.0N 48.2W 55 KT 65 MPH...POST-TROP/EXTRATROP 36H 17/1800Z...ABSORBED WITHIN A FRONTAL ZONE $$ FORECASTER BERG/AVILA |