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#7833 (Received by flhurricane at: 10:56 AM 10.Sep.2004) TCDAT4 HURRICANE IVAN DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT FRI SEP 10 2004 VISIBLE SATELLITE IMAGES SHOW THAT THE CLOUD PATTERN ASSOCIATED WITH IVAN DOES NOT APPEAR AS WELL ORGANIZED AS IT WAS YESTERDAY. HOWEVER...THERE ARE PLENTY OF BANDING FEATURES AND WELL-ESTABLISHED OUTFLOW. YOU CAN SEE THE CONVECTIVE RING ASSOCIATED WITH THE EYEWALL ON HIGH RESOLUTION VISIBLE IMAGES. SUPER RAPID SCAN IR IMAGES SHOW THE VERY STRONG CONVECTIVE RING CURRENTLY RE-DEVELOPING AROUND THE EYE. DATA FROM A RECONNAISSANCE PLANE INDICATE THAT THE SURFACE PRESSURE HAS RISEN TO 934 MB BUT THE FLIGHT LEVEL WINDS REMAIN AT 144 KNOTS. THIS SUPPORTS AN INITIAL INTENSITY OF 125 KNOTS. SOME FLUCTUATIONS IN INTENSITY ARE LIKELY BEFORE IVAN MOVES NEAR OR OVER JAMAICA WHERE THE EFFECTS OF THE HIGH TERRAIN MAY WEAKEN THE HURRICANE. IT IS POSSIBLE THAT IVAN WILL RE-STRENGTHEN SOME BETWEEN THE CAYMAN ISLANDS AND CUBA WHERE THE OCEAN IS QUITE WARM. ONCE IN THE GULF OF MEXICO...THE SHEAR IS FORECAST TO INCREASE AND IVAN SHOULD GRADUALLY WEAKEN. IVAN IS EXPECTED TO REMAIN A DANGEROUS HURRICANE UNTIL IT REACHES THE UNITED STATES. THE HURRICANE IS MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 10 KNOTS...STEERED BY THE SUBTROPICAL RIDGE OVER THE BAHAMAS. AS THE RIDGE WEAKENS...THE STEERING CURRENTS SHOULD WEAKEN TOO...AND THE HURRICANE WILL LIKELY CONTINUE ON A WEST-NORTHWEST TO NORTHWEST TRACK WITH A DECREASE IN FORWARD SPEED. THERE IS STILL HIGH CONFIDENCE IN THIS EARLY PORTION OF THE FORECAST BUT...IT BECOMES UNCERTAIN AFTER THE HURRICANE CROSSES CUBA WHEN GUIDANCE SHOWS THAT THE HURRICANE COULD CONTINUE OVER THE GULF OF MEXICO OR COULD TURN NORTH-NORTHEAST OVER FLORIDA. IN FACT...THIS HAS BEEN THE CASE FOR THE PAST COUPLE OF DAYS. THE OFFICIAL FORECAST DOES NOT FAVOR ONE SCENARIO MORE THAN THE OTHER...AND BRINGS THE HURRICANE NORTHWARD OVER THE GULF OF MEXICO VERY NEAR AND EVENTUALLY OVER FLORIDA. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 10/1500Z 16.5N 75.1W 125 KT 12HR VT 11/0000Z 17.2N 76.5W 125 KT 24HR VT 11/1200Z 18.3N 78.0W 115 KT NEAR JAMAICA 36HR VT 12/0000Z 19.2N 79.0W 120 KT 48HR VT 12/1200Z 20.5N 80.2W 125 KT APPROACHING CUBA 72HR VT 13/1200Z 23.5N 82.0W 110 KT 96HR VT 14/1200Z 28.0N 83.0W 100 KT 120HR VT 15/1200Z 32.5N 82.5W 40 KT INLAND |