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#1151050 (Received by flhurricane at: 4:36 PM 02.Sep.2023) TCDAT5 Post-Tropical Cyclone Idalia Discussion Number 29 NWS National Hurricane Center Miami FL AL102023 500 PM AST Sat Sep 02 2023 Winds on Bermuda have been gradually decreasing since earlier this morning, and weather stations on the island are no longer measuring sustained tropical-storm-force winds (at standard elevation). Gusts to tropical storm force will likely continue on Bermuda into tonight while Idalia pulls away from the island, but the Bermuda Weather Service has elected to discontinue the Tropical Storm Warning in favor of local warnings. Therefore, this will be the last NHC advisory on Idalia. Earlier ASCAT showed that maximum winds remain 50 kt on the northwestern side of the attached frontal boundary. Little change in strength is expected during the next few days. The extratropical cyclone is likely to occlude again in about 3 days and begin to fill, at which point weakening is expected. The NHC intensity forecast is between the HCCA and IVCN consensus aids. Idalia appears to have turned toward the east-northeast, or 075/6 kt. A shortwave trough is expected to move off the coast of New England on Sunday, causing the cyclone to turn northeastward and the northward and speed up over the next 2-3 days. Once it occludes, it is expected to slow down and meander to the southeast of Nova Scotia on days 4 and 5. Additional information on this system can be found in High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php KEY MESSAGES: 1. Swells from Idalia are forecast to cause life-threatening surf and rip current conditions along portions of the east coast of the United States through Labor Day weekend. 2. Gusts to tropical storm force are likely to continue on Bermuda through tonight. FORECAST POSITIONS AND MAX WINDS INIT 02/2100Z 32.0N 62.7W 50 KT 60 MPH...POST-TROP/EXTRATROP 12H 03/0600Z 32.5N 61.7W 50 KT 60 MPH...POST-TROP/EXTRATROP 24H 03/1800Z 34.0N 60.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 04/0600Z 36.0N 58.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 04/1800Z 38.2N 57.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 60H 05/0600Z 40.1N 57.9W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 05/1800Z 41.3N 58.9W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 06/1800Z 43.2N 60.8W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 07/1800Z 45.1N 59.4W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |