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Tropical Storm Elsa Forecast Discussion Number 31
2021-07-07 22:57:27| National Hurricane Center (Atlantic)
Issued at 500 PM EDT Wed Jul 07 2021 000 WTNT45 KNHC 072057 TCDAT5 Tropical Storm Elsa Discussion Number 31 NWS National Hurricane Center Miami FL AL052021 500 PM EDT Wed Jul 07 2021 Surface synoptic data indicate that the center of Elsa has moved into extreme southern Georgia and, assuming continued weakening since earlier today, the maximum winds are estimated to be 40 kt. This may be a generous estimate of the current intensity since no surface observations of sustained tropical-storm-force winds have been recently received. Elsa should weaken into a tropical depression on Thursday. By early Friday, the dynamical models show some restrengthening of the cyclone as it moves along the Mid-Atlantic coastline. However, the simulated satellite imagery from the global models at that time depict the system resembling a frontal cyclone, so it is dubious as to whether Elsa will be completely tropical in 48 hours. Due to the uncertainty as to when extratropical transition will occur, tropical storm watches have been issued for Long Island and portions of southern New England at this time. The initial motion is northward, or 010/12 kt. Elsa is forecast to turn north-northeastward overnight as it moves around the northwestern periphery of an Atlantic subtropical ridge while accelerating northeastward ahead of a broad mid-level trough over the eastern United States and Canada on Thursday. The official forecast is about the same as the previous one and closely follows the multi-model consensus. Key Messages: 1. Heavy rainfall may result in considerable flash, urban, and isolated moderate river flooding over northern Florida. Heavy rainfall across southeast Georgia, South Carolina, North Carolina, and southeastern Virginia may result inconsiderable flash and urban flooding across southeast Georgia and the Lowcountry of South Carolina. Heavy rainfall across the Northeast and New England Thursday and Friday could lead to isolated flash and urban flooding. 2. Although the center of Elsa is expected to remain inland of the coastline from Georgia through the Carolinas during the next day or two, tropical storm conditions are expected along portions of the coasts of Georgia and South Carolina tonight. Tropical storm conditions are also possible along the coast of the mid-Atlantic and southern New England states by Thursday night or Friday. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 30.8N 83.4W 40 KT 45 MPH...INLAND 12H 08/0600Z 32.8N 82.1W 35 KT 40 MPH...INLAND 24H 08/1800Z 35.6N 79.4W 30 KT 35 MPH...INLAND 36H 09/0600Z 38.8N 75.4W 35 KT 40 MPH...INLAND 48H 09/1800Z 42.0N 70.5W 35 KT 40 MPH...INLAND 60H 10/0600Z 46.0N 64.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 10/1800Z 50.0N 57.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 11/1800Z...DISSIPATED $$ Forecaster Pasch
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