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| #1149750 (Received by flhurricane at: 11:06 PM 27.Aug.2023) TCDAT3 Hurricane Franklin Discussion Number 30 NWS National Hurricane Center Miami FL AL082023 1100 PM EDT Sun Aug 27 2023 Franklin is becoming better organized tonight. A ragged eye has emerged in conventional satellite imagery during the past few hours, and the Air Force Hurricane Hunters reported a closed eyewall during recent passes through the center. Aircraft data indicated the minimum pressure has continued to fall, with a 00 UTC dropsonde reporting a pressure of 964 mb. Since the plane departed, the satellite structure of Franklin has markedly improved, with very cold cloud tops wrapping around the eastern portion of the circulation. The initial intensity of 90 kt is supported by recent objective estimates from UW-CIMSS and a T5.0 subjective Dvorak classification from TAFB at 00 UTC. Recent satellite images suggest the hurricane is finally turning more northward as expected, and the initial motion is north-northwestward (330/7 kt). A gradual turn to the north and north-northeast is forecast during the next couple of days as Franklin moves around the western periphery of a high pressure ridge. The track guidance is in good agreement on this portion of the forecast, and only minor westward adjustments were made following the latest HCCA and TVCA aids. Thereafter, track uncertainty increases regarding Franklin`s interaction with a deep-layer trough moving off the U.S. east coast by midweek. The GFS and ECMWF lie on opposite sides of the guidance envelope, with an 850 n-mi spread at 96 h. Given the greater than normal uncertainty, the NHC track forecast remains close to the multi-model consensus aids at days 3-5, showing a gradually faster east-northeastward to northeastward motion during this period. Based on recent satellite trends, it appears that the shear has weakened and the inner core of Franklin has become more solidified. Thus, the hurricane could be primed to strengthen in the near term within a low shear environment over very warm SSTs. The NHC forecast brings Franklin to major hurricane intensity in 12 h with more strengthening thereafter, in best agreement with some of the regional hurricane models and slightly above the HCCA/IVCN aids. As the hurricane recurves, increased deep-layer shear and cooler waters should induce some weakening, although the wind field will expand while the hurricane moves further into the mid-latitudes. This forecast shows Franklin becoming extratropical at day 5, although the timing could be refined based on future track forecasts. Although the core of Franklin is forecast to pass west and north of Bermuda during the next few days, its expanding wind field will likely require a tropical storm watch for the island on Monday. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 26.4N 70.5W 90 KT 105 MPH 12H 28/1200Z 27.3N 71.0W 100 KT 115 MPH 24H 29/0000Z 28.9N 71.2W 110 KT 125 MPH 36H 29/1200Z 30.4N 70.7W 115 KT 130 MPH 48H 30/0000Z 32.2N 69.5W 110 KT 125 MPH 60H 30/1200Z 33.8N 67.3W 100 KT 115 MPH 72H 31/0000Z 35.2N 64.2W 95 KT 110 MPH 96H 01/0000Z 37.5N 57.0W 80 KT 90 MPH 120H 02/0000Z 42.0N 49.5W 65 KT 75 MPH...POST-TROP/EXTRATROP $$ Forecaster Reinhart |
