Official Discussion issued by the National Hurricane Center

Zeta (AL282020) DATA RELEASED: 10/26/2020 10:00:00 AM UTC

Copy of official data

Tropical Storm Zeta Discussion Number   8
NWS National Hurricane Center Miami FL       AL282020
1000 AM CDT Mon Oct 26 2020

After a significant strengthening episode early this morning, Zeta 
appears to have changed little in intensity recently. High spatial 
and temporal resolution GOES-16 visible satellite images indicate 
that the low-level center of the storm is located near the 
northwestern edge of the main area of vigorous deep convection.  The 
current intensity estimate is held at 60 kt which is the average of 
recent Dvorak estimates from TAFB and SAB.  An Air Force Reserve 
Hurricane Hunter aircraft is scheduled to investigate Zeta in a few 
hours, and should provide a better estimate of the strength of the 
storm.

Zeta is moving northwestward, or about 305/9 kt.  A mid-level high 
pressure area centered just east of Florida should steer the 
tropical cyclone on a continued northwestward heading for the next 
day or so, taking center over the northern part of the Yucatan 
Peninsula.  By around 48 hours, Zeta is expected to turn northward 
over the Gulf along the western side of the high. Afterward, a 
shortwave trough moving into the southern Plains should induce a 
turn toward the north-northeast and take the center inland over the 
southern United States.  The system should then move fairly quickly 
northeastward across the eastern U.S. and emerge into the Atlantic 
by day 4.  The official track forecast has been adjusted a bit to 
the west of the previous one but not quite as far west as the 
corrected model consensus.

Zeta is apparently experiencing some north-northwesterly shear given 
the displacement of the low-level center from the convection. 
However, this shear is expected to abate very soon, and the cyclone 
is likely to strengthen into a hurricane before reaching the 
northeastern Yucatan Peninsula.  Some weakening should occur while 
Zeta interacts with land during the next 12 to 24 hours. The 
atmospheric and oceanic environment should be somewhat conducive 
while the system moves over the southern Gulf of Mexico in a day or 
two, and the official forecast shows some re-strengthening in 24-36 
hours.  Later in the forecast period, when Zeta approaches the 
northern Gulf Coast, cooler shelf waters and some increase in 
southwesterly shear could cause some weakening.  The official 
intensity forecast is similar to the previous ones and shows Zeta 
still near hurricane strength at landfall along the northern 
Gulf of Mexico coast, which is near or above most of the model 
guidance.  Zeta is likely to become an extratropical cyclone when it 
emerges into the Atlantic, and be absorbed by a frontal system 
around the end of the forecast period.

Given the timing of the track and the forecast wind radii, watches
will likely be required for a portion of the northern Gulf Coast
later today.

KEY MESSAGES:

1. Hurricane conditions and dangerous storm surge are expected in 
portions of the northern Yucatan Peninsula of Mexico tonight and 
early Tuesday.  Tropical storm conditions could occur over extreme 
western Cuba beginning later today.

2. Through Tuesday, heavy rainfall is expected from Zeta across the
Yucatan Peninsula of Mexico, the Cayman Islands, and central to
western Cuba. This rainfall may lead to flash flooding in urban
areas.  Between Tuesday night and Thursday, heavy rainfall is
expected from portions of the central U.S. 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.

3. Zeta is forecast to be at or near hurricane strength when it
approaches the northern Gulf Coast on Wednesday, and there is an
increasing risk of dangerous storm surge, wind, and rainfall 
impacts from Louisiana to the Florida Panhandle. Residents in these 
areas should monitor the progress of Zeta, as Hurricane and Storm 
Surge watches will likely be issued later today. 

FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 19.1N  85.3W   60 KT  70 MPH
12H  27/0000Z 20.1N  86.7W   75 KT  85 MPH
24H  27/1200Z 21.5N  88.8W   65 KT  75 MPH
36H  28/0000Z 23.3N  90.8W   70 KT  80 MPH
48H  28/1200Z 25.7N  91.8W   70 KT  80 MPH
60H  29/0000Z 28.9N  90.7W   65 KT  75 MPH
72H  29/1200Z 33.0N  87.0W   35 KT  40 MPH...INLAND
96H  30/1200Z 40.0N  73.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  31/1200Z...DISSIPATED

$$
Forecaster Pasch