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| #981634 (Received by flhurricane at: 4:42 PM 08.Sep.2019) TCDAT3 Tropical Storm Gabrielle Discussion Number 22 NWS National Hurricane Center Miami FL AL082019 500 PM AST Sun Sep 08 2019 The convective structure of Gabrielle now consists of a very well defined curved band that envelops the center, which is evident by recent microwave data as well as satellite imagery. An earlier scatterometer pass partially sampled the eastern semicircle of the cyclone and indicated the tropical storm force winds had expanded to 90 n mi from the center in the northeastern quadrant. The latest subjective Dvorak intensity estimate from TAFB has increased to 55 kt, which will the initial intensity for this advisory. Gabrielle will continue to move over warm SSTs and in a moderately favorable atmospheric environment for the next 24 hours. Based on these factors and the improved structure of the cyclone today, some slight strengthening is expected into tonight. Although not implicitly shown in the forecast, it is possible that Gabrielle may reach hurricane intensity sometime tonight or early tomorrow. By tomorrow afternoon, the cyclone will move over cooler waters and southwesterly shear will increase, which should cause a weakening trend to begin. By 48 hours, Gabrielle is expected to merge with a cold front and become an extratropical cyclone. The official forecast is essentially an update of the previous one, and is near the corrected consensus HCCA. The anticipated recurvature has begun and the initial motion is now 350/14 kt. Gabrielle will turn to the northeast by Monday as the system rounds the western periphery of a mid-level ridge centered near the Azores. Once Gabrielle turns northeastward, it will become embedded in the increasing southwesterly flow ahead of the approaching mid-latitude trough, which will accelerate the cyclone`s forward motion. The official forecast was nudged a little west from the previous advisory due to a slight westward shift in the tightly clustered track guidance. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 35.3N 49.4W 55 KT 65 MPH 12H 09/0600Z 37.3N 48.7W 60 KT 70 MPH 24H 09/1800Z 40.0N 46.3W 60 KT 70 MPH 36H 10/0600Z 42.5N 42.4W 55 KT 65 MPH 48H 10/1800Z 45.2N 37.1W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 11/1800Z 52.3N 21.9W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 12/1800Z...DISSIPATED $$ Forecaster Latto |
