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#110415 (Received by flhurricane at: 10:55 AM 12.Sep.2006) TCDAT2 TROPICAL STORM GORDON DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072006 1100 AM EDT TUE SEP 12 2006 A MICROWAVE PASS FROM 0730 UTC...A 1023 WINDSAT PASS AND VISIBLE SATELLITE IMAGERY WERE INSTRUMENTAL IN LOCATING THE CENTER OF GORDON. SATELLITE INTENSITY ESTIMATES FROM TAFB...SAB AND AFWA AVERAGE 50 KT...WHICH IS THE INITIAL INTENSITY FOR THIS ADVISORY. VISIBLE AND WATER VAPOR IMAGERY INDICATE WEAK SOUTHWESTERLY SHEAR OVER THE CYCLONE WHICH IS RESTRICTING THE OUTFLOW IN THE SOUTHWEST QUADRANT AND MAY ALSO BE RESPONSIBLE FOR THE TEMPORARY LEVELING OFF IN THE INTENSITY. THE INITIAL MOTION IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS ADVISORY...345/8. GORDON IS LOCATED ON THE SOUTHWESTERN PERIPHERY OF A NARROWING MID- TO UPPER-LEVEL RIDGE WITH A PRONOUNCED BREAK IN THE SUBTROPICAL RIDGE ASSOCIATED WITH FLORENCE TO ITS NORTH. A LARGE UPPER-LEVEL LOW...LOCATED ABOUT 1000 NMI TO THE NORTHEAST OF GORDON IS MOVING WESTWARD AND IS FORECAST TO WEAKEN THE RIDGE AS INDICATED BY THE GLOBAL MODELS. THIS WILL ALLOW GORDON TO TURN NORTHWARD AND SLOWLY RECURVE AFTER 48 HOURS. ALL OF THE DYNAMICAL MODELS SUPPORT THIS SCENARIO. THE GFS...WHICH HAD BEEN AN OUTLIER...NOW ALSO RECURVES GORDON. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND IS CLOSE TO THE DYNAMICAL CONSENSUS. THE INTENSITY FORECAST IS A BLEND OF THE SHIPS AND FSU SUPERENSEMBLE AND NOT AS AGGRESSIVE AS THE GFDL WHICH MAKES GORDON A 95 KT HURRICANE IN 48 HOURS. GORDON IS FORECAST TO BECOME A HURRICANE IN 24 HOURS. WATER VAPOR IMAGERY SHOWS VERY DRY AIR WEST OF THE AFOREMENTIONED UPPER LOW WHICH COULD BE ONE POSSIBLE INHIBITING FACTOR IN THE INTENSITY FORECAST. TOWARD THE END OF THE FORECAST PERIOD...AS THE CYCLONE BEGINS TO RECURVE OVER COOLER WATERS AND ENCOUNTERS WESTERLY SHEAR...GORDON SHOULD BEGIN WEAKENING. FORECAST POSITIONS AND MAX WINDS INITIAL 12/1500Z 23.4N 58.3W 50 KT 12HR VT 13/0000Z 24.4N 58.6W 55 KT 24HR VT 13/1200Z 25.8N 58.8W 65 KT 36HR VT 14/0000Z 27.4N 58.8W 75 KT 48HR VT 14/1200Z 29.0N 58.5W 75 KT 72HR VT 15/1200Z 32.0N 57.5W 75 KT 96HR VT 16/1200Z 35.0N 54.5W 70 KT 120HR VT 17/1200Z 39.0N 49.0W 60 KT $$ FORECASTER COBB/PASCH |