000 WTNT41 KNHC 020901 TCDAT1 HURRICANE FELIX DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062007 500 AM EDT SUN SEP 02 2007 FELIX HAS RAPIDLY STRENGTHENED OVERNIGHT. AN AIR FORCE RECONNAISSANCE AIRCRAFT MEASURED MAXIMUM FLIGHT-LEVEL WINDS OF 93 KT AND A CENTRAL PRESSURE OF 984 MB DURING THE LAST EYE PENETRATION AT ABOUT 0638Z. IN ADDITION...AN EYEWALL DROPSONDE MEASURED SURFACE WINDS OF 85 KT DERIVED FROM THE MEAN WIND IN THE LOWER LAYER OF THE SOUNDING. BASED ON THESE DATA THE ADVISORY INTENSITY IS SET TO 85 KT. WHILE THE EYE HAS NOT YET BECOME DISCERNIBLE IN CONVENTIONAL GOES INFRARED IMAGERY...IT IS CLEARLY EVIDENT IN RADAR IMAGERY FROM CURACAO AND IN PASSIVE MICROWAVE IMAGERY FROM A TRMM OVERPASS AT 0619Z. FELIX CONTINUES ON A PATH JUST NORTH OF DUE WEST OR 275/16...WITH STEERING PROVIDED BY A STRONG DEEP-LAYER RIDGE OVER THE WESTERN ATLANTIC. THIS RIDGE IS FORECAST BY THE MODELS TO BUILD WESTWARD...PREVENTING FELIX FROM GAINING ANY SIGNIFICANT LATITUDE DURING THE NEXT FEW DAYS. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON A CONTINUATION OF THE CURRENT MOTION FOR THE NEXT 48-72 HOURS. EVEN THE NOGAPS...AN EARLIER NORTHERN OUTLIER...HAS SHIFTED SOUTH AND BACK INTO THE REST OF THE GUIDANCE ENVELOPE. BEYOND 72 HOURS...THE MODELS TAKE VARIOUS PATHS ACROSS CENTRAL AMERICA...WITH THE MOST SOUTHERN SOLUTION PROVIDED BY THE GFDL. THE NEW OFFICIAL FORECAST IS ADJUSTED JUST SLIGHTLY TO THE SOUTH...MOSTLY TO ACCOUNT FOR THE INITIAL MOTION. THE FORECAST AT 4-5 DAYS IS RATHER UNCERTAIN AND DEPENDS ON JUST HOW MUCH RIDGING IS PRESENT OVER THE GULF OF MEXICO AT THAT TIME. ALL FACTORS POINT TO CONTINUED INTENSIFICATION...AND THE NEW OFFICIAL FORECAST IS ADJUSTED UPWARD MAINLY TO REFLECT THE OVERNIGHT STRENGTHENING JUST OBSERVED...AND SO IS HIGHER THAN MOST OF THE OBJECTIVE GUIDANCE. FELIX APPEARS ON ITS WAY TO BECOMING A MAJOR HURRICANE OVER THE CARIBBEAN...BUT HOW MUCH LAND IT TRAVERSES BEYOND 48 HOURS MAKES THE LONG-RANGE INTENSITY FORECAST VERY UNCERTAIN. FORECAST POSITIONS AND MAX WINDS INITIAL 02/0900Z 12.8N 68.7W 85 KT 12HR VT 02/1800Z 13.2N 71.3W 95 KT 24HR VT 03/0600Z 13.9N 75.0W 105 KT 36HR VT 03/1800Z 14.6N 78.6W 115 KT 48HR VT 04/0600Z 15.3N 81.9W 125 KT 72HR VT 05/0600Z 16.5N 87.0W 120 KT 96HR VT 06/0600Z 18.0N 91.0W 70 KT...INLAND 120HR VT 07/0600Z 20.0N 94.5W 70 KT...OVER WATER $$ FORECASTER KNABB