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| #1149312 (Received by flhurricane at: 10:45 PM 24.Aug.2023) TCDAT3 Tropical Storm Franklin Discussion Number 18 NWS National Hurricane Center Miami FL AL082023 1100 PM AST Thu Aug 24 2023 Franklin is still a strongly sheared tropical storm, with deep convection displaced to the east and southeast of the surface center. An Air Force Reserve Hurricane Hunter mission flying at 700 mb this evening fixed a center within the strong thunderstorm activity, but because of the cyclone`s tilted structure, the surface center is estimated to be a few tenths of a degree farther west. SFMR and flight-level winds suggest that the maximum winds could be between 50-55 kt, but the central pressure has risen a few millibars since this morning`s flight. Therefore, the initial intensity is held at 50 kt. Franklin is embedded in the base of a deep-layer trough located over the western Atlantic, which is steering the storm toward the east-northeast (70 degrees) at 7 kt. The parent trough is forecast to lift northeastward and allow mid-level ridging to build over the central Atlantic during the next couple of days, and Franklin is expected to respond by making a sharp but slow northward turn by 36 hours. The ridge could even be strong enough to push Franklin toward the north-northwest for a time while the storm moves across the western Atlantic, and the HAFS regional models in particular favor that scenario, being the westernmost of the guidance suite. Those models have tugged the consensus aids a bit west too, and as a result the new NHC forecast track is nudged in that direction compared to the previous forecast. Moderate to strong deep-layer shear is likely to continue over Franklin for the next 36-48 hours, until the storm makes its northward turn. That said, warm ocean waters and a favorably diffluent upper-level pattern should still allow for gradual strengthening during the next couple of days, and Franklin is expected to become a hurricane by 48 hours, about the time the shear abates. More significant strengthening is likely after 48 hours while Franklin moves over the western Atlantic, and the NHC intensity forecast remains close to the HCCA and IVCN consensus aids. The HAFS regional models continue to show stronger solutions, so trends in the other models will have to be monitored for potential upward adjustments to the official forecast in the coming days. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 22.6N 68.3W 50 KT 60 MPH 12H 25/1200Z 22.9N 67.5W 50 KT 60 MPH 24H 26/0000Z 23.2N 66.7W 55 KT 65 MPH 36H 26/1200Z 23.7N 66.6W 60 KT 70 MPH 48H 27/0000Z 24.8N 67.0W 65 KT 75 MPH 60H 27/1200Z 26.1N 67.7W 75 KT 85 MPH 72H 28/0000Z 27.8N 68.1W 90 KT 105 MPH 96H 29/0000Z 31.9N 68.2W 95 KT 110 MPH 120H 30/0000Z 37.1N 65.6W 85 KT 100 MPH $$ Forecaster Berg |
