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#106204 (Received by flhurricane at: 4:55 AM 26.Aug.2006) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052006 500 AM EDT SAT AUG 26 2006 AN AIR FORCE PLANE HAS BEEN INVESTIGATING ERNESTO AND FOUND THAT THE CENTRAL PRESSURE DROPPED TO 999 MB WITH A WELL-ESTABLISHED CYCLONIC CIRCULATION. HOWEVER FLIGHT LEVEL WINDS HAVE NOT INCREASED MUCH SINCE THE PREVIOUS FLIGHT. IT APPEARS THAT THE CENTER IS LOCATED ON THE WESTERN PORTION OF THE LARGE DEEP CONVECTIVE MASS DUE TO THE CURRENT SOUTHWESTERLY WIND SHEAR. ALTHOUGH DVORAK INTENSITY ESTIMATES SUPPORT 45 KNOTS...THE INITIAL INTENSITY IS KEPT AT 40 KNOTS BASED ON AVAILABLE REPORTS FROM THE AIRCRAFT. ERNESTO HAS BEEN A FIGHTER AND HAS BEEN ABLE TO SURVIVE THE STRONG SHEAR SO FAR. UNANIMOUSLY...ALL GLOBAL MODELS DEVELOP AN UPPER-LEVEL RIDGE OVER ERNESTO...A PATTERN WHICH IS CONDUCIVE FOR STRENGTHENING. THIS UPPER-LEVEL PATTERN COMBINED WITH THE VERY WARM WATERS AHEAD OF THE CYCLONE COULD LEAD TO SIGNIFICANT STRENGTHENING OVER THE NEXT FEW DAYS. THIS COULD RESULT IN ERNESTO BECOMING A POWERFUL HURRICANE IN THE GULF OF MEXICO. THE INTENSITY FORECAST IS LOWER THAN THE GFDL AND VERY SIMILAR TO SHIPS AND FSU SUPERENSEMBLE. OF COURSE...THE INTENSITY FORECAST IS HIGHLY UNCERTAIN AND STRENGTHENING MAY NOT OCCUR AT ALL IF THE SHEAR DOES NOT DECREASE. FIXES FROM THE RECONNAISSANCE PLANE INDICATE THAT ERNESTO IS MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 14 KNOTS AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE. THIS GENERAL TRACK IS EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD WITH A DECREASE IN FORWARD SPEED IN A DAY OR TWO AS THE RIDGE TO THE NORTH WEAKENS. THE OFFICIAL TRACK FORECAST IS IN THE MIDDLE OF THE MODEL ENVELOPE BUT CLOSER TO THE GLOBAL MODEL CONSENSUS. IN SUMMARY...ERNESTO COULD BECOME A POTENTIALLY DANGEROUS HURRICANE AS IT MOVES ACROSS THE NORTHWESTERN CARIBBEAN SEA AND THE GULF OF MEXICO. INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0900Z 14.8N 70.2W 40 KT 12HR VT 26/1800Z 15.4N 72.2W 50 KT 24HR VT 27/0600Z 16.6N 74.8W 55 KT 36HR VT 27/1800Z 18.0N 77.5W 60 KT 48HR VT 28/0600Z 19.5N 80.0W 70 KT 72HR VT 29/0600Z 22.0N 83.5W 80 KT 96HR VT 30/0600Z 24.0N 86.5W 90 KT 120HR VT 31/0600Z 26.0N 89.0W 100 KT |