000 WTNT42 KNHC 150243 TCDAT2 TROPICAL STORM RAFAEL DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172012 1100 PM AST SUN OCT 14 2012 THE CLOUD PATTERN OF THE STORM HAS BECOME A LITTLE BETTER ORGANIZED ON SATELLITE IMAGES OVER THE PAST SEVERAL HOURS...WITH MORE DISTINCT CURVED BAND FEATURES NOTED TO THE NORTHWEST...NORTH... NORTHEAST...AND EAST OF THE CENTER. THE AIR FORCE HURRICANE HUNTERS MEASURED PEAK 850 MB FLIGHT-LEVEL WINDS OF 71 KT AND AN SFMR SURFACE WIND OF 59 KT TO THE NORTH-NORTHWEST OF THE CENTER. CORRECTING FOR RAINFALL REDUCES THIS SFMR VALUE TO 54 KT...BUT IT IS PRESUMED THAT SLIGHTLY STRONGER SURFACE WINDS ARE OCCURRING OVER THE NORTHEAST QUADRANT...SO THE CURRENT INTENSITY ESTIMATE IS INCREASED TO 60 KT. RAFAEL HAS FAIRLY WELL-DEFINED UPPER-LEVEL OUTFLOW OVER THE NORTHERN AND EASTERN PORTIONS OF ITS CIRCULATION. ALTHOUGH THE SOUTHWESTERLY SHEAR OVER THE CYCLONE IS LIKELY TO BE MODERATE TO STRONG OVER THE NEXT DAY OR TWO...THE INCREASE IN ORGANIZATION AND THE LATEST STATISTICAL-DYNAMICAL INTENSITY MODEL GUIDANCE INDICATE THAT RAFAEL COULD STRENGTHEN SOME MORE IN THE SHORT TERM. IN 2-3 DAYS...HOWEVER...THE SHEAR IS FORECAST TO INCREASE TO 30 TO 40 KT AS A LARGE UPPER-TROPOSPHERIC TROUGH APPROACHES THE TROPICAL CYCLONE...WHICH SHOULD INDUCE WEAKENING. BY 96 HOURS...GLOBAL MODEL OUTPUT SHOWS CONSIDERABLE COLD AIR ADVECTION OVER THE WESTERN PORTION OF THE CIRCULATION...SO THE SYSTEM IS FORECAST TO BECOME AN EXTRATROPICAL CYCLONE BY THAT TIME. THE MOTION REMAINS NORTH-NORTHWESTWARD...OR 330/9...AND THE FORECAST STEERING SCENARIO REMAINS ABOUT THE SAME AS BEFORE. RAFAEL IS EXPECTED TO TURN NORTHWARD AND NORTHEASTWARD WITH INCREASING FORWARD SPEED OVER THE NEXT FEW DAYS AS IT MOVES BETWEEN A MID-LATITUDE TROUGH AND A SUBTROPICAL HIGH PRESSURE AREA. BY LATE IN THE FORECAST PERIOD...GLOBAL GUIDANCE SHOWS THE EXTRATROPICAL CYCLONE SLOWING DOWN AS IT INTERACTS WITH ANOTHER LOW OVER THE NORTHEASTERN ATLANTIC. THERE ARE CONSIDERABLE DIFFERENCES IN THE FORWARD SPEED PREDICTED BY THE DYNAMICAL MODELS OVER THE NEXT 3 DAYS OR SO...WITH THE ECMWF SHOWING A SUBSTANTIALLY SLOWER MOTION THAN MOST OF THE OTHER TRACK GUIDANCE. THE OFFICIAL TRACK FORECAST IS SIMILAR TO THAT FROM THE PREVIOUS ADVISORY AND LEANS TOWARD THE LATEST GFS ENSEMBLE MEAN FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 15/0300Z 21.6N 64.8W 60 KT 70 MPH 12H 15/1200Z 22.8N 65.6W 65 KT 75 MPH 24H 16/0000Z 24.8N 65.9W 70 KT 80 MPH 36H 16/1200Z 27.5N 65.0W 70 KT 80 MPH 48H 17/0000Z 31.5N 62.6W 65 KT 75 MPH 72H 18/0000Z 40.5N 55.0W 60 KT 70 MPH 96H 19/0000Z 48.0N 39.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 20/0000Z 49.0N 26.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ FORECASTER PASCH