ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Zeta Discussion Number   4
NWS National Hurricane Center Miami FL       AL282020
1100 AM EDT Sun Oct 25 2020

Although the cloud pattern of the storm is not well-organized and 
somewhat elongated zonally, the system is producing very vigorous 
deep convection, particularly over the southern portion of the 
circulation.  Cirrus cloud motions show that the upper-level 
outflow is well-defined.  The current intensity estimate remains at 
35 kt in agreement with Dvorak values from both TAFB and SAB, and 
pending another Hurricane Hunter mission into the system this 
afternoon.  

The center is difficult to locate at this time, and the best 
estimate for motion is quasi-stationary.  A high pressure area 
developing near Florida should induce a general northwestward 
motion over the next couple of days.  Later, a shortwave trough 
approaching from the west is likely to cause Zeta to turn northward 
and north-northeastward while it nears the northern Gulf Coast in 
72-84 hours.  The official track forecast lies between the GFS 
solution which is farther east and the ECMWF prediction which lies 
farther south and west.

Given the favorable upper-level outflow pattern and very high 
oceanic heat content over the northwestern Caribbean, strengthening 
is likely until the center moves near or over the Yucatan Peninsula 
late tomorrow.  Zeta should be near or at hurricane strength when it 
approaches the Yucatan.  The official intensity forecast for the 
next 36 hours is close to the model consensus.  After Zeta moves 
into the central Gulf of Mexico, increasing southwesterly shear and 
diminishing oceanic heat content are expected to prevent 
strengthening.  The NHC intensity forecast over the Gulf is above 
the latest model consensus.  Although not explicitly shown in the 
official forecast, the unfavorable atmospheric and oceanic 
conditions over the northern Gulf of Mexico could cause Zeta 
to weaken by the time the center nears the northern Gulf coast.  
However, users are reminded that these intensity forecasts are 
subject to uncertainty.

KEY MESSAGES:
 
1. Tropical storm conditions are expected in portions of the 
northern Yucatan Peninsula of Mexico Monday night and early Tuesday, 
with hurricane conditions possible.  Tropical storm conditions 
could occur over extreme western Cuba on Monday.
 
2. Through Wednesday, heavy rainfall is expected from Zeta across 
portions of central and western Cuba, the Cayman Islands, Jamaica, 
the northeast Yucatan peninsula of Mexico, southern Florida and the 
Keys. This rainfall may lead to flash flooding in urban areas.
 
3. Zeta could be at or just below hurricane strength when it 
approaches the northern Gulf Coast on Wednesday, and could bring 
storm surge, rainfall, and wind impacts to areas from Louisiana to 
the Florida Panhandle. Residents in these areas should monitor the 
progress of Zeta and updates to the forecast.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 17.8N  83.8W   35 KT  40 MPH
 12H  26/0000Z 18.4N  84.1W   40 KT  45 MPH
 24H  26/1200Z 19.2N  85.1W   50 KT  60 MPH
 36H  27/0000Z 20.3N  86.7W   60 KT  70 MPH
 48H  27/1200Z 21.9N  88.7W   65 KT  75 MPH
 60H  28/0000Z 24.0N  90.3W   65 KT  75 MPH
 72H  28/1200Z 27.0N  90.5W   65 KT  75 MPH
 96H  29/1200Z 35.0N  85.5W   25 KT  30 MPH...INLAND
120H  30/1200Z...DISSIPATED
 
$$
Forecaster Pasch
 
NNNN