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#981567 (Received by flhurricane at: 4:50 AM 08.Sep.2019) TCDAT3 Tropical Storm Gabrielle Discussion Number 20 NWS National Hurricane Center Miami FL AL082019 500 AM AST Sun Sep 08 2019 Gabrielle has become a little better organized overnight. The storm now has well-defined curved bands, especially to the south of the center, with some evidence of an inner core trying to form. The initial intensity is nudged upward to 50 kt, which is between the Dvorak classification from TAFB and the latest satellite consensus estimate from the CIMSS at the University of Wisconsin. Earlier ASCAT data revealed that Gabrielle is a compact storm with its tropical-storm-force winds only extending out to about 60 n mi from the center. The tropical storm is gradually turning to the right, with the initial motion estimated to be northwestward at 11 kt. The system is located near the southwestern periphery of a mid-level ridge centered near the Azores, and it should be moving around the western side of that ridge later today and tonight. This should cause Gabrielle to turn northward with some increase in forward speed during that time. An even faster northeastward motion is expected on Monday and Tuesday as Gabrielle, or its post-tropical remnants, become embedded in the mid-latitude westerlies. The track models are in fairly good agreement, and only minor adjustments were made to the previous forecast. Gabrielle could strengthen a little more today while it remains over warm water and in generally favorable atmospheric conditions. However, the combined influences of increasing southerly shear and cooler waters should end the chances of intensification on Monday. The global models are in agreement that Gabrielle should become extratropical when it merges with a cold front that is associated with Post-Tropical Cyclone Dorian in a little more than 2 days. The extratropical low is expected to gradually weaken and ultimately dissipate in 4 to 5 days. The NHC intensity forecast is largely an update of the previous one and in line with the majority of the intensity guidance. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 32.7N 48.6W 50 KT 60 MPH 12H 08/1800Z 34.3N 49.2W 55 KT 65 MPH 24H 09/0600Z 37.1N 48.5W 55 KT 65 MPH 36H 09/1800Z 40.1N 45.7W 55 KT 65 MPH 48H 10/0600Z 42.7N 41.0W 55 KT 65 MPH 72H 11/0600Z 48.1N 28.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 12/0600Z 56.0N 10.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 13/0600Z...DISSIPATED $$ Forecaster Cangialosi |