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#1150806 (Received by flhurricane at: 11:02 AM 01.Sep.2023) TCDAT3 Hurricane Franklin Discussion Number 48 NWS National Hurricane Center Miami FL AL082023 1100 AM AST Fri Sep 01 2023 The latest satellite images of Franklin indicate the system is gradually losing tropical characteristics. The inner circulation of the system is exposed, with a curved band of deep convection displaced to the east of its center by strong westerly shear. The low-level center is also losing definition and appears more elongated than yesterday. A cold front is racing southeastward toward Franklin, with rope clouds evident in visible satellite imagery over the northern Atlantic. Recent scatterometer data shows peak winds of 55-60 kt to the west of the center, with a larger area of 34-kt winds in the northwest quadrant due to the approaching front. Based on these data, the initial intensity is set at 65 kt. In the short term, Franklin appears likely to remain at or near hurricane-force intensity due to baroclinic forcing while it merges with a frontal system over the northern Atlantic. This scenario is supported by all the global models, which show a narrow band of strong winds persisting within the western portion of the circulation during the next 12-24 h (consistent with the aforementioned ASCAT data). Soon thereafter, the extratropical cyclone is forecast to weaken as the low moves deeper into the mid-latitudes and gradually fills. The updated NHC intensity forecast lies between the GFS and ECMWF in the near term, and then trends toward the multi-model consensus later in the period. Franklin is moving northeastward (50 degrees/16 kt) within the flow between a deep-layer trough over the northwestern Atlantic and a subtropical ridge over the central Atlantic. A somewhat faster motion to the northeast is anticipated during the next day or so, followed by a continued northeastward to east-northeastward motion into early next week. Through 72 h, the updated NHC forecast lies close to the previous prediction. As discussed with prior forecasts, track uncertainty grows beyond day 3 regarding how much interaction will occur between Franklin and a larger cut-off low meandering over the eastern Atlantic. The latest NHC track has been adjusted south of the previous forecast at days 4-5, but future adjustments could be necessary as it still lies north of the TVCA and HCCA aids. FORECAST POSITIONS AND MAX WINDS INIT 01/1500Z 38.7N 55.6W 65 KT 75 MPH 12H 02/0000Z 40.1N 52.4W 70 KT 80 MPH...POST-TROP/EXTRATROP 24H 02/1200Z 42.5N 47.8W 65 KT 75 MPH...POST-TROP/EXTRATROP 36H 03/0000Z 44.7N 43.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 03/1200Z 46.5N 39.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 60H 04/0000Z 47.9N 34.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 04/1200Z 48.6N 31.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 05/1200Z 49.0N 28.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 06/1200Z 49.5N 22.0W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Reinhart |