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| #1018386 (Received by flhurricane at: 11:09 AM 22.Sep.2020) TCDAT5 Hurricane Teddy Discussion Number 41 NWS National Hurricane Center Miami FL AL202020 1100 AM AST Tue Sep 22 2020 Teddy is in the late stages of extratropical transition. The hurricane has taken on a large comma shape in satellite images, with a huge dry-air intrusion aloft near the center and a cold front on the western side of the cyclone. While it is tempting to call it an extratropical now, temperature data from a NOAA Hurricane Hunter aircraft indicate that Teddy has maintained a significant warm core, and the strongest winds on the southwestern side appear to be more related to the cyclone and not the front. Lastly, deep convection is trying to re-develop near the center, another indication that the transition is not yet done. Thus Teddy will remain a hurricane on this advisory. The initial wind speed is set to 90 kt, a blend of the 122-kt flight-level winds, 75-kt SFMR values, and global model analyses since much of this large hurricane is not being sampled. Teddy should transition into a post-tropical cyclone by the time it reaches Nova Scotia and steadily weaken as it moves over the cooler waters north of the Gulf Stream. The cyclone should turn northward today and north-northeastward tomorrow ahead of the next trough in the mid-latitudes. This will take Post-Tropical Teddy over Nova Scotia and near Newfoundland during the next couple of days, with the cyclone likely being absorbed into a larger extratropical cyclone west of Greenland in 2-3 days. There are no significant changes to report, except to show a sooner dissipation, which is consistent with the latest global models solutions. The hurricane-force and tropical-storm-force winds fields, plus 12-ft seas area, from Teddy have just about doubled overnight, so it is important to note that hazards will extend much farther than normal from the center of this hurricane. The NOAA Hurricane Hunter reported hurricane-force surface winds 120 n mi northwest of the center, and Canadian buoy 44150 has recently reported 34-ft significant wave heights, with the buoy still about 180 n mi from the center. Key Messages: 1. Teddy is expected to transition to a powerful post-tropical cyclone as it moves near or over portions of Atlantic Canada late today through Thursday. The most significant hazard expected from Teddy is large destructive waves forecast along the southern coast of Nova Scotia through Wednesday. 2. Very large swells produced by Teddy are expected to affect portions of Bermuda, the Leeward Islands, the Greater Antilles, the Bahamas, the east coast of the United States, and Atlantic Canada during the next few days. These swells are expected to cause life-threatening surf and rip current conditions. 3. Tropical Storm Watches and Warnings are in effect for portions of Nova Scotia, Prince Edward Island and Newfoundland, and heavy rainfall across Atlantic Canada is expected with Teddy through Thursday. FORECAST POSITIONS AND MAX WINDS INIT 22/1500Z 39.6N 63.7W 90 KT 105 MPH 12H 23/0000Z 41.8N 64.1W 75 KT 85 MPH 24H 23/1200Z 44.8N 62.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 24/0000Z 48.8N 59.3W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 24/1200Z 54.0N 54.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 60H 25/0000Z...DISSIPATED $$ Forecaster Blake |