000 WTNT42 KNHC 110848 TCDAT2 HURRICANE FRED DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072009 500 AM AST FRI SEP 11 2009 THERE HAS NOT BEEN ANY RECENT MICROWAVE IMAGERY OVER FRED...SO IT HAS BEEN DIFFICULT TO DIAGNOSE ANY STRUCTURAL CHANGES. OVERALL... CONVECTION REMAINS QUITE STRONG NEAR THE MID-LEVEL CENTER...WITH DVORAK INTENSITY ESTIMATES HOLDING STEADY NEAR 77 KT. YET SATELLITE IMAGERY SHOWS THAT THE CLOUD PATTERN IS BECOMING ELONGATED FROM THE SOUTHWEST TO NORTHEAST...WITH EVEN SOME HINTS THAT THE LOW-LEVEL CENTER IS WELL SOUTHWEST OF THE MID-LEVEL CENTER. FOR NOW...THE INITIAL WIND SPEED IS HELD AT 75 KT...BUT THAT ESTIMATE COULD BE A LITTLE HIGH. THE INTENSITY FORECAST APPEARS STRAIGHTFORWARD WITH 20-30 KT OF SOUTHWESTERLY SHEAR LIKELY CAUSING STEADY WEAKENING OVER THE NEXT 48 HOURS...WITH EVEN STRONGER SHEAR THEREAFTER. ALTHOUGH SSTS ARE MARGINALLY WARM...THE EXPECTED SLOW MOTION OF FRED SHOULD CAUSE UPWELLING OF COOLER WATERS AND HELP TO DIMINISH CONVECTION NEAR THE CENTER. THE NHC FORECAST CONTINUES THE TREND OF THE PREVIOUS FORECAST AND IS SIMILAR TO THE SHIPS MODEL. IT APPEARS THAT FRED HAS TURNED TOWARD THE NORTH OR 000/3. LITTLE NET MOTION IS EXPECTED OVER THE NEXT DAY OR TWO WITH A MID-LEVEL TROUGH TO ITS NORTHWEST PERHAPS NUDGING THE TROPICAL CYCLONE A LITTLE NORTHEASTWARD. ONCE FRED WEAKENS INTO A SHALLOWER SYSTEM...THE CYCLONE SHOULD TURN NORTHWESTWARD AND WEST-NORTHWESTWARD WITH AN INCREASE IN FORWARD SPEED UNDER THE INFLUENCE OF A REBUILDING SURFACE RIDGE. THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS ONE THROUGH 48 HR THEN IS SHIFTED TO THE WEST AFTERWARDS...A LITTLE SOUTH OF THE MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 11/0900Z 17.7N 35.1W 75 KT 12HR VT 11/1800Z 17.9N 35.0W 60 KT 24HR VT 12/0600Z 18.0N 34.8W 50 KT 36HR VT 12/1800Z 18.2N 34.6W 40 KT 48HR VT 13/0600Z 18.6N 34.7W 35 KT 72HR VT 14/0600Z 20.0N 37.5W 25 KT 96HR VT 15/0600Z 21.5N 42.0W 20 KT...REMNANT LOW 120HR VT 16/0600Z 22.5N 47.5W 20 KT...REMNANT LOW $$ FORECASTER BLAKE