ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Hurricane Zeta Discussion Number 16 NWS National Hurricane Center Miami FL AL282020 1000 AM CDT Wed Oct 28 2020 Zeta has a well-organized cloud pattern on satellite images, and the eye has been fairly well-defined. Strong upper-level outflow is evident over the northern semicircle of the hurricane. Reports from Air Force and NOAA Hurricane Hunter aircraft indicate that the system had continued to strengthen over the past few hours. Peak 700-mb flight level winds were 89 kt, which equates to a maximum surface wind of about 80 kt, and The central pressure has fallen to 976 mb. Zeta still has a few hours to intensify before it begins to move over the cooler waters of the northern Gulf of Mexico, and southwesterly shear is likely to increase by the time the center reaches the coast. Even if a little weakening begins later today, however, Zeta should maintain hurricane strength through landfall. The official intensity forecast is near the high end of the model guidance. In 36 hours or so, the global models clearly depict the system as a frontal wave approaching the United States east coast so the official forecast shows an extratropical cyclone at that point and beyond. After 48 hours, the models show the low becoming elongated and absorbed into the frontal zone. The hurricane has turned northward and is now moving at around 010/16 kt. A strong 500-mb trough moving into Texas will continue to move eastward during the next 36-48 hours. The flow ahead of this trough will cause Zeta to accelerate north-northeastward and move inland along the central Gulf Coast in 6-12 hours. On Thursday, the cyclone will then move northeastward on the east side of the trough, at an even faster pace, over the southeastern United States. By early Friday, the system should move east- northeastward in the westerlies and into the western Atlantic as an extratropical cyclone. The official track forecast is close to the previous one and generally follows the dynamical model consensus. Given Zeta's acceleration near and after landfall, strong winds are likely to spread well inland over the southeastern U.S. this evening and early Thursday. KEY MESSAGES: 1. A life-threatening storm surge is expected along portions of the northern Gulf Coast beginning later today, with the highest inundation occurring between Port Fourchon, Louisiana, and Dauphin Island, Alabama. Residents in the Storm Surge Warning area should follow any advice given by local officials. Overtopping of local, non-federal levee systems is possible within southeastern Louisiana outside of the Hurricane and Storm Damage Risk Reduction System. 2. Hurricane conditions are expected this afternoon and evening within portions of the Hurricane Warning area along the southeastern Louisiana and Mississippi coasts. Tropical storm conditions are expected within portions of the Tropical Storm Warning area along the Alabama and far western Florida Panhandle coasts. 3. Strong, damaging wind gusts, which could cause tree damage and power outages, will spread well inland across portions of southeastern Mississippi, Alabama, northern Georgia, the Carolinas, and southeastern Virginia tonight and Thursday due to Zeta's fast forward speed. Wind gusts could be especially severe across the southern Appalachian Mountains on Thursday. 4. Through Thursday, heavy rainfall is expected from portions of the central U.S. Gulf Coast into the Mid-Mississippi Valley, Ohio Valley, southern to central Appalachians, and Mid-Atlantic States near and in advance of Zeta. This rainfall will lead to flash, urban, small stream, and minor river flooding. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 26.9N 91.7W 80 KT 90 MPH 12H 29/0000Z 30.1N 89.9W 80 KT 90 MPH...INLAND 24H 29/1200Z 35.3N 83.9W 40 KT 45 MPH...INLAND 36H 30/0000Z 39.1N 74.2W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 30/1200Z 41.5N 63.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 60H 31/0000Z...DISSIPATED $$ Forecaster Pasch NNNN