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| #1108129 (Received by flhurricane at: 11:03 PM 20.Sep.2022) TCDAT2 Hurricane Fiona Discussion Number 27 NWS National Hurricane Center Miami FL AL072022 1100 PM EDT Tue Sep 20 2022 Data from a NOAA Hurricane Hunter aircraft that has been investigating Fiona this evening show that the hurricane has strengthened since this afternoon. The aircraft has measured peak 700-mb flight-level winds of 120 kt, and SFMR winds of around 110 kt earlier in the evening. Based on those data, the intensity was increased to 110 kt on the intermediate advisory at 0000 UTC. Since that time, the satellite presentation has continued to improve with the eye becoming better defined and the surrounding ring of deep convection expanding with colder cloud top temperatures. The pressure has fallen a few more millibars and is now down to 947 mb, however the plane has not found any higher winds during several passes through the northeastern and northern portion of the eyewall. It is worth noting that the latest subjective and objective satellite estimates suggest a stronger intensity, and this may be a case in which the winds are lagging the improved satellite presentation, which is not too uncommon. The vertical wind shear over the hurricane is expected to remain low to moderate during the next couple of days. During that time, the hurricane will be traversing SSTs of 29-30 degrees Celsius, and remain in a moist environment. These conditions should allow for some additional strengthening during the next 12 to 24 hours, but after that time, difficult-to-predict eyewall replacement cycles are likely to cause some fluctuations in intensity. By day 3, the system is forecast to interact with a vigorous mid-troposphere trough and the system is expected to become a large and powerful extratropical cyclone near Atlantic Canada. The latest satellite and aircraft fixes indicate that the hurricane is now moving just west of due north or 350/7 kt. Fiona should move generally northward around the western periphery of a mid-level ridge during the next 24 hours. After that time, the hurricane is forecast to turn north-northeastward and begin to gradually accelerate as the aforementioned trough approaches from the northwest. Very little cross-track changes were made to the latest NHC forecast, but it is slightly slower than the previous advisory to be in better agreement with the bulk of the dynamical models. Key Messages: 1. Heavy rains south of Fiona will continue to impact the Turks and Caicos through tonight with additional flooding possible. 2. Tropical storm conditions are possible on Bermuda by late Thursday. 3. Fiona is expected to affect portions of Atlantic Canada as a powerful hurricane-force cyclone late Friday and Saturday, and could produce significant impacts from high winds, storm surge, and heavy rainfall. Interests in these areas should closely monitor the progress of Fiona and updates to the forecast. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 23.2N 71.8W 110 KT 125 MPH 12H 21/1200Z 24.3N 71.9W 120 KT 140 MPH 24H 22/0000Z 26.0N 71.5W 120 KT 140 MPH 36H 22/1200Z 28.1N 70.8W 120 KT 140 MPH 48H 23/0000Z 30.8N 69.0W 120 KT 140 MPH 60H 23/1200Z 34.3N 65.6W 115 KT 130 MPH 72H 24/0000Z 39.5N 61.8W 105 KT 120 MPH 96H 25/0000Z 48.3N 59.7W 65 KT 75 MPH...POST-TROP/EXTRATROP 120H 26/0000Z 55.4N 58.7W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown |
