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| #1108478 (Received by flhurricane at: 5:02 AM 23.Sep.2022) TCDAT2 Hurricane Fiona Discussion Number 36 NWS National Hurricane Center Miami FL AL072022 500 AM AST Fri Sep 23 2022 Fiona is feeling the first effects of the mid-latitude westerlies, with the eye becoming less distinct during the past few hours and the central convection becoming more ragged. In addition, satellite imagery shows a cold front approaching the cyclone from the west. However, these changes have not yet caused much change in strength. An earlier Air Force Reserve Hurricane Hunter mission found the central pressure was 936 mb, and it reported 132-kt 700-mb flight-level winds in the southeastern eyewall. The maximum surface wind estimates from the SFMR were under 100 kt, so the initial intensity of 110 kt is a compromise between the SFMR winds and the higher intensity suggested by the flight-level wind. Fiona is accelerating to the north-northeast with the initial motion now 030/22 kt. Interaction with the strong deep-layer trough moving eastward into the northwestern Atlantic should cause the hurricane to speed up further during the next day or so, reaching peak speeds of 30-35 kt as it approaches Nova Scotia. As stated in the previous advisory, Fiona should merge with the trough soon after 24 hours, slow down a bit, but continue moving northward across Atlantic Canada to the Labrador Sea during the balance of the forecast period. There are no significant changes to the track guidance for this advisory, and the new track forecast is an update of the previous forecast. Fiona should start to undergo extratropical transition during the next 12 h, with the transition likely to be complete just after the 24 h point. While the cyclone will weaken some during the transition, it is expected to remain a powerful hurricane-force cyclone as it crosses Nova Scotia into the Gulf of St. Lawrence. Continued weakening is expected after that, and winds could drop below gale force by day 5 when the post-tropical low is over the Labrador Sea. The new intensity forecast had some minor adjustments from the previous forecast and it follows the overall trend of the intensity guidance, including the global models. Key Messages: 1. Hurricane conditions are expected on Bermuda overnight. Conditions should diminish below tropical storm force during the day on Friday. 2. Fiona is expected to affect portions of Atlantic Canada as a powerful hurricane-force cyclone late Friday and Saturday, and significant impacts from high winds, storm surge, and heavy rainfall are likely. Hurricane and Tropical Storm Warnings have now been issued for much of Atlantic Canada. 3. Large swells generated by Fiona are expected to cause life-threatening surf and rip current conditions along much of the east coast of the United States, the Bahamas, Bermuda, and Atlantic Canada during the next few days. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 33.8N 66.8W 110 KT 125 MPH 12H 23/1800Z 37.9N 63.9W 110 KT 125 MPH 24H 24/0600Z 43.2N 62.0W 100 KT 115 MPH 36H 24/1800Z 47.0N 61.1W 75 KT 85 MPH...POST-TROP/EXTRATROP 48H 25/0600Z 50.1N 59.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 60H 25/1800Z 53.8N 58.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 26/0600Z 57.5N 58.3W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 27/0600Z 62.5N 57.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 28/0600Z 65.0N 57.0W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Beven |
