|
Show Selection: |
| #1022829 (Received by flhurricane at: 11:06 AM 27.Oct.2020) TCDAT3 Tropical Storm Zeta Discussion Number 12 NWS National Hurricane Center Miami FL AL282020 1000 AM CDT Tue Oct 27 2020 High-resolution GOES-16 visible satellite images indicate that the center of Zeta has moved just offshore of the northern coast of Yucatan. Based on Air Force and NOAA aircraft observations a little while ago, after the cyclone`s interaction with the Yucatan, the maximum winds had decreased to near 55 kt. The cloud pattern of the storm is well organized, with a small Central Dense Overcast and numerous banding features. Given this, Zeta is likely to restrengthen as it moves over the warm waters of the southern Gulf of Mexico and in a low-shear environment today through tomorrow morning. When the cyclone nears the northern Gulf Coast in 30-36 hours, decreasing oceanic heat content and possibly stronger shear will likely halt the intensification process. The official intensity forecast shows slight weakening near landfall, but Zeta is likely to be at or near hurricane strength when it crosses the coastline. The NHC intensity forecast is close to the model consensus and a blend of the LGEM and Decay-SHIPS guidance. The storm continues its generally northwestward motion, or at around 305/12 kt. Zeta will move northwestward to northward around the southwestern and western periphery of a mid-level high pressure area centered east of Florida for the next 24 hours or so. Then, a strong 500-mb shortwave trough approaching from the west should cause Zeta to accelerate north-northeastward to northeastward by late Wednesday and Thursday. This will bring Zeta across the north-central Gulf coast late Wednesday and over the southeastern United States on Thursday. Aside from some speed differences, the track models are in good agreement and have shown good run-to-run consistency. The official track forecast is about the same as the previous one and close to the model consensus. Given Zeta`s acceleration near landfall, strong winds are likely to spread well inland along the northern Gulf coast Wednesday night. KEY MESSAGES: 1. A life-threatening storm surge is expected along portions of the northern Gulf Coast by late Wednesday, with the highest inundation occurring somewhere between the Mouth of the Pearl River and Dauphin Island, Alabama. Residents in the Storm Surge Warning area should follow any advice given by local officials. 2. Hurricane conditions are expected by late Wednesday within portions of the Hurricane Warning area between Morgan City, Louisiana, and the Mississippi/Alabama border. Damaging winds, especially in gusts, will spread well inland across portions of southeast Mississippi and southern Alabama Wednesday night due to Zetas fast forward speed. 3. Between tonight and Thursday, heavy rainfall is expected from portions of the central U.S. Gulf Coast into the Ohio Valley and Mid-Atlantic States near and in advance of Zeta. This rainfall will lead to flash, urban, small stream, and minor river flooding. 4. Tropical storm conditions will continue in portions of the northern Yucatan Peninsula of Mexico during the next few hours. Heavy rainfall is expected across the Yucatan Peninsula, the Cayman Islands, and western Cuba today, which will lead to flash flooding in urban areas. FORECAST POSITIONS AND MAX WINDS INIT 27/1500Z 21.6N 89.5W 55 KT 65 MPH 12H 28/0000Z 23.1N 90.9W 70 KT 80 MPH 24H 28/1200Z 25.7N 91.6W 75 KT 85 MPH 36H 29/0000Z 29.3N 89.9W 70 KT 80 MPH 48H 29/1200Z 34.2N 85.2W 30 KT 35 MPH...INLAND 60H 30/0000Z 38.5N 76.5W 30 KT 35 MPH...INLAND 72H 30/1200Z 41.0N 66.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 31/1200Z...DISSIPATED $$ Forecaster Pasch |