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| #1017690 (Received by flhurricane at: 11:03 PM 18.Sep.2020) TCDAT5 Hurricane Teddy Discussion Number 27 NWS National Hurricane Center Miami FL AL202020 1100 PM AST Fri Sep 18 2020 Teddy continues to have an impressive appearance on satellite images with a fairly symmetrical Central Dense Overcast, although recent images show some warming of the cloud tops over the southeastern part of the circulation. Upper-level outflow is well-defined over the northern semicircle of the hurricane and not as strong to the south. Earlier microwave images showed a concentric eyewall structure and it appears that the hurricane has re-intensified slightly over the past several hours. The current intensity estimate is set at 115 kt which is a blend of subjective and objective Dvorak estimates. Some additional fluctuations in strength as a result of eyewall replacements could occur through Saturday. On Sunday and beyond, a less conducive oceanic and atmospheric environment should lead to slow weakening. However, Teddy should remain a powerful hurricane for the next several days. The numerical guidance shows that the circulation will become even larger during the forecast period due to Teddy combined with a high pressure area coming behind a cold front over the eastern United States. Teddy is expected to make the transition to an extratropical cyclone when it moves into Atlantic Canada. The hurricane continues its northwestward trek and is moving around 325/11 kt. Teddy should move around the western side of a subtropical high pressure system for the next day or so. Then, the cyclone should turn northward with an increase in forward speed as it approaches a strong mid-latitude trough cutting off into a low as it moves off the northeast U.S. coast in 2-3 days. The track of the system could bend a bit the left as it interacts with the trough/low while approaching Nova Scotia. Around the end of the forecast period, the post-tropical cyclone should turn northeastward as it moves along the eastern side of a mid-level trough. The official track forecast is close to the corrected model consensus. Teddy is producing seas to 48 feet and an extensive area of large waves and swells which are impacting much of the western Atlantic basin. See the Key Messages below. Key Messages: 1. While the center of Teddy is forecast to move east of Bermuda late Sunday or Monday, there is still a risk of strong winds, storm surge, and heavy rainfall on the island, and a Tropical Storm Watch is in effect. 2. Teddy is expected to transition to a powerful post-tropical cyclone as it moves near or over portions of Atlantic Canada early next week, where there is an increasing risk of direct impacts from wind, rain, and storm surge. Residents there should closely monitor the progress of Teddy and updates to the forecast through the weekend. 3. Large swells produced by Teddy are expected to affect portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, the east coast of the United States, and Atlantic Canada during the next few days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 24.0N 57.4W 115 KT 130 MPH 12H 19/1200Z 25.5N 58.6W 115 KT 130 MPH 24H 20/0000Z 27.3N 60.4W 110 KT 125 MPH 36H 20/1200Z 29.0N 61.8W 105 KT 120 MPH 48H 21/0000Z 30.8N 62.3W 100 KT 115 MPH 60H 21/1200Z 33.5N 61.4W 95 KT 110 MPH 72H 22/0000Z 37.7N 61.1W 85 KT 100 MPH 96H 23/0000Z 45.5N 62.5W 70 KT 80 MPH...POST-TROP/EXTRATROP 120H 24/0000Z 50.5N 56.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |
