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#1022758 (Received by flhurricane at: 10:57 PM 26.Oct.2020) TCDAT3 Hurricane Zeta Discussion Number 10 NWS National Hurricane Center Miami FL AL282020 1000 PM CDT Mon Oct 26 2020 Satellite images are showing that convection has been increasing near Zeta tonight, with cold cold tops to at least -93C, and occasional hints of a warm spot related to the early-stages of an eye beneath the clouds. Yet, the NOAA Hurricane Hunter aircraft mission found that Zeta has basically been steady state in terms of maximum winds and pressures, with peak SFMR values hovering between 65-70 kt and dropsonde data showing central pressures of about 982 mb. The data did show that the area of hurricane-force winds has grown, about 40 n mi in the eastern semicircle, and it is possible that the worst of this hurricane will be after the center makes landfall. The initial wind speed is kept at 70 kt on this advisory. The hurricane is running out of time to get much stronger before landfall during the next couple of hours, but some increase in intensity is possible. Zeta should spend less than 12 hours over land as it crosses Yucatan, but that`s enough time to probably drop it below hurricane strength early tomorrow. However, environmental conditions are unseasonably conducive for intensification so late in the year in the southern and central Gulf of Mexico, with fairly light shear and warm waters during the next 24 to 36 hours. The peak intensity forecast is raised slightly after considering those factors, and some models like the HWRF or ECMWF even suggest it could get a little stronger. As the hurricane nears the northern Gulf Coast, it is likely to encounter stronger shear and cooler waters, so some weakening is anticipated, but Zeta is still expected to be at or near hurricane intensity at landfall. The NHC intensity forecast is generally similar to the previous one, lying above the model consensus. Zeta continues to move on a generally northwestward track, or about 305/11 kt. The hurricane should move around the southwestern and western periphery of a mid-level subtropical high centered just east of Florida. Thereafter, a potent shortwave trough approaching from the Desert Southwest and Texas is likely to cause the cyclone to accelerate north-northeastward to northeastward on Wednesday and move over the southeastern and eastern United States. Model guidance is in very good agreement, with only some minor differences, and the new forecast is close to the previous one and the models consensus. The system should move off the Mid-Atlantic U.S. coast and become an extratropical cyclone within 3 days, and dissipate soon thereafter. KEY MESSAGES: 1. Hurricane conditions and dangerous storm surge are expected to continue in portions of the northern Yucatan Peninsula of Mexico through early Tuesday. Heavy rainfall is expected across the Yucatan Peninsula, the Cayman Islands, and western Cuba through Tuesday, which could lead to flash flooding in urban areas. 2. Hurricane conditions and life-threatening storm surge are possible along portions of the northern Gulf Coast on Wednesday, and Storm Surge and Hurricane Watches are in effect. Residents in the watch areas should follow any advice given by local officials. 3. Between Tuesday night and Thursday, heavy rainfall is expected from portions of the central Gulf Coast into the southern 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 27/0300Z 20.2N 87.1W 70 KT 80 MPH 12H 27/1200Z 21.3N 88.8W 60 KT 70 MPH...INLAND 24H 28/0000Z 23.1N 90.7W 65 KT 75 MPH...OVER WATER 36H 28/1200Z 25.6N 91.6W 75 KT 85 MPH 48H 29/0000Z 29.1N 90.1W 65 KT 75 MPH 60H 29/1200Z 33.8N 85.7W 35 KT 40 MPH...INLAND 72H 30/0000Z 38.5N 76.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 31/0000Z...DISSIPATED $$ Forecaster Blake |