000 WTNT43 KNHC 161442 TCDAT3 TROPICAL STORM BILL DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009 1100 AM AST SUN AUG 16 2009 BILL IS DISPLAYING A BEAUTIFUL CURVED BAND PATTERN ON SATELLITE IMAGERY THIS MORNING WITH A NEW BURST OF CONVECTION OCCURRING NEAR THE CENTER. A 0808 UTC QUIKSCAT PASS SHOWED MAXIMUM WINDS OF AT LEAST 45 KT...AND DVORAK SATELLITE INTENSITY ESTIMATES ARE BETWEEN 45-55 KT. THE INITIAL INTENSITY IS SET TO 50 KT AS A BLEND OF THE ABOVE DATA. A SERIES OF MICROWAVE PASSES AND VISIBLE IMAGES HAVE CONFIRMED THAT THE CENTER HAS SHIFTED A LITTLE BIT TO THE NORTH AND THE INITIAL MOTION IS ABOUT 285/14. A CONTINUED WEST-NORTHWEST MOTION IS EXPECTED FOR THE NEW FEW DAYS DUE TO SUBTROPICAL RIDGING TO THE NORTH OF BILL. ALL OF THE GLOBAL MODELS BESIDES THE UKMET SHOW THE TROPICAL CYCLONE MOVING TO THE NORTH OF THE LEEWARD ISLANDS AS A BREAK IN THE RIDGE FORMS AT ABOUT 65W. MODEL GUIDANCE HAS SHIFTED TO THE NORTHEAST THIS MORNING...AND THE OFFICIAL FORECAST FOLLOWS THAT TREND. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR CONTINUED INTENSIFICATION DUE TO LIGHT SHEAR AND WARM WATERS. SSTS BEGIN TO RISE MORE SIGNIFICANTLY IN A COUPLE OF DAYS AND THE NHC INTENSITY FORECAST COULD BE CONSERVATIVE AFTER THAT TIME. ALL RELIABLE GUIDANCE SHOWS THIS SYSTEM EVENTUALLY BECOMING A MAJOR HURRICANE... THOUGH AT DIFFERING TIME PERIODS WITH THE STATISTICAL GUIDANCE SHOWING IT HAPPENING EARLIER THAN THE DYNAMICAL MODELS. THE NHC FORECAST IS RAISED FROM THE PREVIOUS ONE...AND IS IN GOOD AGREEMENT WITH THE SHIPS/LGEM THROUGH 72 HOURS. THE INTENSITY FORECAST IS LEVELED OFF AFTER 96 HOURS DUE THE POSSIBILITY OF WESTERLY SHEAR DEVELOPING...AS SUGGESTED BY THE GFS/ECMWF MODELS. THE QUIKSCAT PASS FROM THIS MORNING SHOWED THAT THE WIND FIELD WITH BILL HAS EXPANDED...AND CONSEQUENTLY THE INITIAL 12 FT SEAS AND FORECAST WIND RADII ARE LARGER THAN THE PREVIOUS FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 16/1500Z 12.1N 38.4W 50 KT 12HR VT 17/0000Z 12.6N 40.4W 60 KT 24HR VT 17/1200Z 13.4N 43.1W 70 KT 36HR VT 18/0000Z 14.3N 45.9W 80 KT 48HR VT 18/1200Z 15.2N 48.6W 90 KT 72HR VT 19/1200Z 17.5N 54.0W 100 KT 96HR VT 20/1200Z 20.5N 59.0W 105 KT 120HR VT 21/1200Z 24.0N 63.5W 105 KT $$ FORECASTER BLAKE