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Hurricane Teddy Forecast Discussion Number 37
2020-09-21 16:54:45| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Mon Sep 21 2020 000 WTNT45 KNHC 211454 TCDAT5 Hurricane Teddy Discussion Number 37 NWS National Hurricane Center Miami FL AL202020 1100 AM AST Mon Sep 21 2020 Teddy has weakened some since yesterday. While the maximum 700-mb winds from the latest Air Force Reserve Hurricane Hunter aircraft mission were 93 kt, the peak SFMR values were only 68 kt. A blend of these data with some undersampling due to the large size of Teddy gives an initial wind speed of 80 kt. The hurricane is beginning to accelerate to the north-northeast as the long-awaited mid-latitude trough begins to pick up the cyclone. All of the guidance is in very good agreement that Teddy will benefit from this interaction, growing in both size and maximum winds due to this trough and warmer waters in the Gulf Stream. Thus, the hurricane should intensify overnight, and the new intensity forecast is close to the latest GFS model. Afterward, the baroclinic energy source is exhausted, and Teddy should move north of the Gulf Stream by Wednesday, helping to complete its post-tropical transition. The cyclone should weaken while it accelerates to the north-northeast across eastern Nova Scotia, the Gulf of St. Lawrence, and Newfoundland before dissipating in 3-4 days. No significant changes were made to the track forecast. Teddy's size will likely increase substantially during the next couple of days as it moves northward and interacts with the aforementioned frontal system. Gale force winds are likely along portions of the near shore waters of the northeast U.S. Please see products from your local office for more information about marine hazards. Key Messages: 1. The center of Teddy is forecast to move east of Bermuda today. Wind gusts of tropical-storm-force have been reported on the island, and tropical storm conditions could continue today. 2. Teddy is expected to transition to a powerful post-tropical cyclone as it moves near or over portions of Atlantic Canada late Tuesday through Thursday, where there is an increasing risk of direct impacts from wind, rain, and storm surge. A Tropical Storm Watch is in effect for portions of Nova Scotia, and heavy rainfall across Atlantic Canada is expected with Teddy between Tuesday and Thursday after it becomes a strong post-tropical cyclone. 3. 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 will likely cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 31.1N 62.7W 80 KT 90 MPH 12H 22/0000Z 34.4N 62.4W 85 KT 100 MPH 24H 22/1200Z 38.2N 63.7W 90 KT 105 MPH 36H 23/0000Z 40.7N 64.3W 80 KT 90 MPH 48H 23/1200Z 43.7N 63.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 60H 24/0000Z 47.5N 60.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 24/1200Z 51.5N 55.5W 45 KT 50 MPH...POST-TROP/INLAND 96H 25/1200Z...DISSIPATED $$ Forecaster Blake
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