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| #1108055 (Received by flhurricane at: 10:56 AM 20.Sep.2022) TCDAT2 Hurricane Fiona Discussion Number 25 NWS National Hurricane Center Miami FL AL072022 1100 AM EDT Tue Sep 20 2022 Fiona has not changed much in organization on satellite images over the past several hours, with the eye obscured on visible satellite imagery. Upper-level outflow is still somewhat restricted over the western semicircle of the system. A recent SSMIS microwave image suggested that the hurricane may be undergoing an eyewall replacement. Observations from Air Force and NOAA Hurricane Hunter aircraft indicate that the central pressure has not changed much from earlier this morning. Flight-level and SFMR-observed surface winds from the aircraft do not support an intensity higher than 100 kt, so the intensity is held at that value for this advisory. This is also in agreement with Dvorak satellite estimates from TAFB and SAB, and recent NOAA Synthetic Aperture Radar data. Numerical guidance indicates that Fiona will continue to be influenced by moderate west-southwesterly shear during the next couple of days. However the models also indicate that the thermodynamic environment will be conducive for intensification over the next 48 hours, as Fiona passes through a moist air mass and over warm SSTs of 28-29 deg. The official intensity forecast continues to call for Fiona becoming a category 4 hurricane, in agreement with the corrected consensus model guidance, HCCA. Beyond 72 hours, the hurricane is expected to interact with a vigorous mid-latitude trough moving into the Atlantic from the northeastern United States. This should start the process of extratropical transition by 96 hours, with the transition complete by the end of the forecast period. Fiona is expected to remain a deep and strong cyclone after extratropical transition. Fiona continues to move north-northwestward, at about 330/8 kt. The track guidance has changed very little from the previous advisory. Over the next couple of days, the hurricane should continue to move around the western periphery of a mid-level high pressure system centered to its east. in 48-96 hours, Fiona is expected to move north-northeastward to northeastward with increasing forward speed along the southeast side of a strong mid-tropospheric trough. The official track forecast is similar to the previous NHC prediction and in close agreement with the HCCA guidance. Key Messages: 1. Heavy rainfall and localized life-threatening flash flooding should continue over portions of the Dominican Republic today. Heavy rains should continue to impact the Turks and Caicos through this afternoon with continued life-threatening flooding. Localized additional flash and urban flooding is possible in Puerto Rico. 2. Hurricane conditions are affecting portions of the Turks and Caicos islands, while tropical storm conditions should affect portions of 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 20/1500Z 22.0N 71.4W 100 KT 115 MPH 12H 21/0000Z 23.0N 71.7W 105 KT 120 MPH 24H 21/1200Z 24.4N 71.8W 110 KT 125 MPH 36H 22/0000Z 26.1N 71.2W 115 KT 130 MPH 48H 22/1200Z 28.3N 70.2W 120 KT 140 MPH 60H 23/0000Z 31.1N 68.4W 115 KT 130 MPH 72H 23/1200Z 34.7N 65.2W 110 KT 125 MPH 96H 24/1200Z 45.0N 60.0W 85 KT 100 MPH 120H 25/1200Z 52.0N 59.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |
