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Tropical Storm Eta Discussion Number   2
NWS National Hurricane Center Miami FL       AL292020
1100 PM EDT Sat Oct 31 2020

Satellite imagery indicates that shower activity associated with the 
cyclone continues to become better organized, with a convective band 
wrapping about halfway around the center.  Satellite intensity 
estimates from TAFB and SAB have increased to 35 kt, and the CIMSS 
satellite consensus is near 40 kt.  Based on these data, the 
depression is upgraded to Tropical Storm Eta, the twenty-eighth 
named storm of the 2020 season.  This ties the record for storms set 
in the 2005 season and is the first time the name Eta has been used 
in the Atlantic basin.

The initial motion is 275/13.  A low- to mid-level ridge axis that 
extends from the subtropical Atlantic southwestward to Cuba and the 
Bahamas is currently the main steering influence, and the model 
guidance is in good agreement that this feature should cause the 
storm to move westward for the next 24-36 h.  Between 36-72 h, a 
building low- to mid-level ridge over the Gulf of Mexico should 
cause Eta to turn west-southwestward as it approaches the coasts of 
Nicaragua and Honduras.  Beyond that time, there remains 
significant spread in the models, with the GFS showing a slow 
motion toward the northwest near the coast of Honduras while the 
ECMWF/UKMET show a continued west-southwestward motion into the 
Pacific.  Given the spread, the NHC official track forecast shows 
a slow motion on days 3 through 5, and brings the cyclone's center 
slowly across portions of Nicaragua and Honduras.  The new forecast 
track is close to the multi-model consensus, and the 72-120 h part 
remains low confidence.

Eta is over warm water and is in environment of light vertical wind 
shear. These conditions are expected to continue until the system 
nears the coast of Central America on 60-72 h.  Thus, steady to 
possibly rapid strengthening is expected, with the storm forecast to 
reach hurricane strength between 36-48 h.  The intensity guidance 
has trended stronger since the last advisory, and this part of the 
new intensity forecast is now a little below the intensity 
consensus.  After 72 h, the intensity forecast is tied to whether or 
not the cyclone's center moves inland over Central America, and the 
current forecast is based on the forecast track that takes the 
center well inland.
 
Key Messages:
 
1. The depression is expected to strengthen to a hurricane early
next week as it approaches the coast of Central America late Monday
and Monday night, and there is a risk of storm surge,
hurricane-force winds, and heavy rainfall for portions of Nicaragua
and Honduras where Hurricane Watches have been issued.  Hurricane 
warnings could be needed for portions of those areas on Sunday.
 
2. Through Thursday evening, heavy rainfall from Eta may lead to 
flash flooding and river flooding across portions of Jamaica, the 
Cayman Islands, and Central America, which could lead to landslides 
in areas of higher terrain.  Flooding is also possible near the 
southern coast of Hispaniola, depending upon the track of the storm.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0300Z 15.0N  74.2W   35 KT  40 MPH
 12H  01/1200Z 15.1N  76.4W   40 KT  45 MPH
 24H  02/0000Z 15.3N  78.8W   50 KT  60 MPH
 36H  02/1200Z 15.2N  80.8W   60 KT  70 MPH
 48H  03/0000Z 14.7N  82.1W   70 KT  80 MPH
 60H  03/1200Z 14.2N  82.8W   80 KT  90 MPH
 72H  04/0000Z 13.7N  83.7W   70 KT  80 MPH...INLAND
 96H  05/0000Z 14.0N  85.5W   35 KT  40 MPH...INLAND
120H  06/0000Z 14.5N  87.0W   25 KT  30 MPH...INLAND
 
$$
Forecaster Beven
 
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