000 WTNT41 KNHC 290249 TCDAT1 TROPICAL STORM OPHELIA DISCUSSION NUMBER 26 NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011 1100 PM AST WED SEP 28 2011 AIRCRAFT DATA INDICATE THAT OPHELIA HAS STRENGTHENED. PEAK FLIGHT-LEVEL WINDS WERE 64 KT...WITH BELIEVABLE SFMR VALUES NEAR 50 KT. THUS THE INITIAL WIND SPEED IS RAISED TO 50 KT. ALTHOUGH THE STORM HAS BECOME A LITTLE STRONGER...INFRARED SATELLITE IMAGES ARE NOT PARTICULARLY IMPRESSIVE WITH A SMALL AREA OF CONVECTION NORTHEAST OF THE CENTER ALONG WITH A LARGER CURVED BAND IN THE SOUTHEAST QUADRANT. MICROWAVE DATA...HOWEVER...DOES SHOW A BETTER-ORGANIZED CORE WITH PERHAPS THE PRIMITIVE STAGES OF AN EYE. IT IS INTERESTING THAT OPHELIA HAS INTENSIFIED A GOOD DEAL TODAY DESPITE AN UPPER-LEVEL TROUGH CAUSING 20-25 KT OF SOUTHWESTERLY SHEAR. AS THIS TROUGH TO THE NORTHWEST OF OPHELIA PULLS AWAY...UPPER RIDGING SHOULD BUILD IN CLOSER TO THE CYCLONE AND CAUSE THE SHEAR TO RELAX TO MORE MODERATE LEVELS. STEADY INTENSIFICATION WOULD SEEM TO BE THE BEST BET...AND THE NHC FORECAST COULD BE ON THE CONSERVATIVE SIDE IF AN INNER CORE BECOMES ORGANIZED. THE NEW FORECAST IS SIMILAR TO THE PREVIOUS ONE BUT SHOWS A HIGHER PEAK INTENSITY AT 72 HOURS...SPLITTING THE DIFFERENCE BETWEEN THE STATISTICAL AND DYNAMICAL GUIDANCE. WEAKENING SHOULD BEGIN AFTER DAY 3 DUE TO COOLING WATERS AND INCREASING SOUTHWESTERLY SHEAR. THE AIRCRAFT FIXES INDICATE THAT CYCLONE IS MOVING A BIT SLOWER... ABOUT 325/5. THE GLOBAL MODELS ARE IN RATHER GOOD AGREEMENT ON OPHELIA PICKING UP SOME FORWARD SPEED AS IT MOVES ON A TRACK TOWARD THE NORTH-NORTHWEST AND NORTH OVER THE NEXT COUPLE OF DAYS ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. THEREAFTER... THE CYCLONE SHOULD START TO ACCELERATE TO THE NORTH-NORTHEAST DUE TO INCREASING SOUTHWESTERLY FLOW BETWEEN THE RIDGE AND A LARGE MID-TROPOSPHERIC TROUGH MOVING OFF THE U.S. EAST COAST. WHILE THE GUIDANCE HAS BEEN STRUGGLING WITH THE INTERACTION OF THE TROPICAL CYCLONE WITH THE MID-LATITUDE FLOW...IN GENERAL THE GUIDANCE HAS SHIFTED A BIT TO THE LEFT AFTER DAY 3...AND THE NHC FORECAST FOLLOWS SUIT. THE MOST CONSISTENT MODEL HAS BEEN THE ECMWF SINCE YESTERDAY...AND THE OFFICIAL FORECAST WILL STAY BETWEEN THAT MODEL AND THE HFIP MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 19.4N 60.7W 50 KT 60 MPH 12H 29/1200Z 20.3N 61.3W 55 KT 65 MPH 24H 30/0000Z 21.9N 62.0W 60 KT 70 MPH 36H 30/1200Z 23.7N 62.8W 65 KT 75 MPH 48H 01/0000Z 26.1N 63.1W 70 KT 80 MPH 72H 02/0000Z 32.5N 62.0W 80 KT 90 MPH 96H 03/0000Z 43.0N 57.5W 65 KT 75 MPH 120H 04/0000Z 54.0N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ FORECASTER BLAKE