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#1023136 (Received by flhurricane at: 4:47 AM 29.Oct.2020) TCDAT3 Tropical Storm Zeta Discussion Number 19 NWS National Hurricane Center Miami FL AL282020 400 AM CDT Thu Oct 29 2020 Surface observations and Doppler radar data indicate that Zeta weakened to a tropical storm around 0600 UTC when it was located over central Alabama. During the past few hours, the cyclone`s structure has degraded further with the center no longer easily apparent in radar images and convection appearing more ragged and asymmetric. The initial intensity is lowered to 50 kt for this advisory, and that could be a little generous. The minimum pressure is estimated to be 988 mb based on surface observations. The storm continues to accelerate, and the latest initial motion is northeastward at 34 kt. Zeta is expected to race northeastward today in the fast steering flow between a potent mid- to upper-level low to its west and a high pressure ridge to its southeast. This pattern should take the cyclone across the southeast and Mid-Atlantic states throughout the day, before emerging over the western Atlantic this evening. An even faster east-northeastward motion is predicted tonight and on Friday until the cyclone dissipates by Friday night. The tropical storm is forecast to weaken a little more during the next several hours as it remains over land, and Zeta will likely become extratropical by the time it reaches the mid-Atlantic states this afternoon. However, after that time, the models show the cyclone leveling off in strength or perhaps even re-intensifying over the western Atlantic before it becomes absorbed into a frontal zone in 36 to 48 hours. The NHC intensity forecast follows the GFS and ECMWF models. KEY MESSAGES: 1. Strong, damaging wind gusts, which could cause tree damage and power outages, will continue to spread well inland across portions of northeastern Alabama, northern Georgia, the Carolinas, and southeastern Virginia today due to Zeta`s fast forward speed. Wind gusts could be especially severe across the southern Appalachian Mountains. 2. Through today, heavy rainfall is expected near and in advance of Zeta from portions of the central Appalachians, Mid-Atlantic and lower to middle Ohio Valley. This rainfall may lead to flash, urban, small stream, and isolated minor river flooding. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 34.0N 85.5W 50 KT 60 MPH...INLAND 12H 29/1800Z 37.7N 79.1W 45 KT 50 MPH...POST-TROP/EXTRATROP 24H 30/0600Z 40.8N 66.9W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 30/1800Z 43.4N 54.6W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 31/0600Z...DISSIPATED $$ Forecaster Cangialosi |