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| #981383 (Received by flhurricane at: 4:45 PM 06.Sep.2019) TCDAT3 Tropical Storm Gabrielle Discussion Number 13 NWS National Hurricane Center Miami FL AL082019 500 PM AST Fri Sep 06 2019 Gabrielle has become somewhat better organized during the past few hours, with a better-defined surface circulation moving closer to a large burst of convection in the northern semicircle. There has been little change in the intensity estimates, so the initial wind speed will stay 40 kt on this advisory. The storm continues to move to the northwest at about 15 kt. A large subtropical ridge to the northeast of Gabrielle is forecast to build westward, forcing the tropical cyclone to turn west- northwestward on Saturday. After that time, southwesterly flow ahead of Hurricane Dorian should turn Gabrielle quickly northward and northeastward by early next week. Other than some minor speed differences, the models continue to be tightly packed. The new NHC track forecast is basically an update of the previous one, and it lies near the NOAA corrected-consensus model. Southerly shear currently near Gabrielle is forecast to relax by late tomorrow, at about the same time that it moves over very warm waters near 29C. This should promote strengthening, and it is possible that Gabrielle could intensify quickly near recurvature. By 96 h, the cyclone should move north of the Gulf Stream, with increasing shear. These conditions should cause a fast extratropical transition between 96-120 h. The new NHC prediction is raised at 48 and 72 hours, and it should be noted that quite a few models show Gabrielle becoming a category 2 hurricane at some point during that time. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 27.9N 39.6W 40 KT 45 MPH 12H 07/0600Z 29.3N 41.7W 45 KT 50 MPH 24H 07/1800Z 30.8N 44.5W 50 KT 60 MPH 36H 08/0600Z 32.2N 47.0W 55 KT 65 MPH 48H 08/1800Z 33.9N 48.4W 65 KT 75 MPH 72H 09/1800Z 38.5N 46.0W 80 KT 90 MPH 96H 10/1800Z 44.0N 38.5W 70 KT 80 MPH 120H 11/1800Z 53.0N 23.0W 60 KT 70 MPH...POST-TROP/EXTRATROP $$ Forecaster Blake |
