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#724685 (Received by flhurricane at: 11:03 PM 15.Oct.2014) TCDAT3 HURRICANE GONZALO DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014 1100 PM AST WED OCT 15 2014 Although satellite images have recently shown increased organization, aircraft data suggest that Gonzalo has actually slightly weakened. An Air Force Reserve Hurricane Hunter aircraft measured peak flight-level winds of 118 kt and a peak SFMR value of 99 kt. These data support an initial intensity of 105 kt. The plane did report that the concentric eyewall cycle has finished, suggesting that the weakening trend is probably over. Little change in strength is shown for the next 24 hours since the shear expected to be weak or moderate while the hurricane traverses warm waters. Gradual weakening is shown after that time due to the cyclone moving across cooler waters, some of which were upwelled by the recent passage of Fay near Bermuda. The official NHC forecast is a little lower than the previous one, although is on the higher side of the guidance during the first 36 hours. Transition to a post-tropical cyclone is expected in about 72 hours with most of the models showing Gonzalo becoming a large warm-seclusion low. Gonzalo is turning northward as it feels the effects of a strong trough over the eastern United States. There is good agreement on the cyclone moving toward the north-northeast tomorrow and northeast on Friday, accelerating as it is steered by the trough. The NHC forecast virtually unchanged over the first couple of days of the prediction, with most of the models showing Gonzalo near Bermuda in a little over 36 hours. At longer range, the extratropical cyclone should move more to the east-northeast as it moves within the fast mid-latitude flow to the north of a central Atlantic ridge. Only small changes were made to the previous forecast, which ends up being slightly slower at days 4 and 5. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 24.6N 68.7W 105 KT 120 MPH 12H 16/1200Z 25.8N 68.7W 105 KT 120 MPH 24H 17/0000Z 28.1N 68.0W 105 KT 120 MPH 36H 17/1200Z 30.7N 66.6W 100 KT 115 MPH 48H 18/0000Z 33.8N 64.8W 90 KT 105 MPH 72H 19/0000Z 43.8N 57.4W 80 KT 90 MPH...POST-TROPICAL 96H 20/0000Z 52.0N 37.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 21/0000Z 55.0N 17.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Blake |