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| #1108014 (Received by flhurricane at: 4:57 AM 20.Sep.2022) TCDAT2 Hurricane Fiona Discussion Number 24 NWS National Hurricane Center Miami FL AL072022 500 AM EDT Tue Sep 20 2022 A few hours ago, an Air Force Reserve Hurricane Hunter aircraft reported that the central pressure of Fiona had dropped to 967 mb, and that the 700-mb flight-level winds were near 95 kt. In addition, the aircraft also reported surface winds estimates from the SFMR of 100-105 kt. The various satellite intensity estimates are in the 100-115 kt range, and based on these data the initial intensity was increased to 100 kt. This makes Fiona the first major hurricane of the 2022 Atlantic hurricane season. It should be noted that since the aircraft left the storm, the eye has become less distinct in satellite imagery. NOAA and Air Force Reserve Hurricane Hunter aircraft are scheduled to investigate Fiona before 12Z to see how much, if any, additional strengthening has occurred. While Fiona has strengthened, satellite imagery continues to show restricted outflow in the western semicircle, likely due to continued southwesterly vertical wind shear. While some shear should continue through 72 h, it appears it will not be strong enough to prevent additional intensification, and Fiona is likely to become a category 4 hurricane during this time. After 72 h, the hurricane will interact with a powerful mid-latitude trough moving into the Atlantic from the eastern United States. This should start the process of extratropical transition by 96 h, with the transition complete by the end of the forecast period. Fiona is expected to remain intense through much of the transition, with the GFS, ECMWF, and UKMET forecasting 85-95 kt winds and unusually low central pressures at 96 h. Fiona has moved northwestward during the past several hours, but a longer-term motion is north-northwestward or 330/9 kt. There is no change in the track forecast philosophy, as during the next 48-60 h the hurricane should gradually turn north while moving around the western periphery of a mid-level ridge. After that, Fiona is forecast to turn north-northeastward and accelerate as it interacts with the aforementioned strong mid-latitude trough, with a northward motion expected after the cyclone completes extratropical transition. The track guidance, while remaining tightly clustered, has shifted a little westward during the first 72 h, and this part of the new forecast track is nudged a little westward as well. Key Messages: 1. Outer bands from Fiona will continue to produce heavy rain over mostly coastal and eastern sections of the Dominican Republic and in local portions of southern Puerto Rico over the next 24 hours as Fiona moves north-northwest over the southwest Atlantic Ocean. Heavy rainfall and localized life-threatening flash flooding will continue over portions of the Dominican Republic today. Heavy rains around the center of Fiona will impact the Turks and Caicos through this afternoon with continued life-threatening flooding. Localized additional flash and urban flooding is possible in the southern portion of Puerto Rico. 2. Hurricane conditions are spreading over the Turks and Caicos islands, while tropical storm conditions should spread over the southeastern Bahamas during the next few hours. 3. Interests in Bermuda should continue to monitor the progress of Fiona. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 21.3N 70.9W 100 KT 115 MPH 12H 20/1800Z 22.3N 71.4W 110 KT 125 MPH 24H 21/0600Z 23.6N 71.7W 115 KT 130 MPH 36H 21/1800Z 25.1N 71.5W 120 KT 140 MPH 48H 22/0600Z 27.1N 70.7W 120 KT 140 MPH 60H 22/1800Z 29.6N 69.4W 120 KT 140 MPH 72H 23/0600Z 32.6N 66.8W 115 KT 130 MPH 96H 24/0600Z 42.5N 60.0W 90 KT 105 MPH 120H 25/0600Z 50.5N 59.5W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Beven |
