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Hurricane Eta Discussion Number  14
NWS National Hurricane Center Miami FL       AL292020
1000 PM EST Tue Nov 03 2020
 
Satellite imagery and surface observation data indicate that 
Hurricane Eta has moved farther inland over northeastern Nicaragua 
this evening. Eta has maintained a well-defined CDO feature in 
infrared satellite data, although passive microwave imagery is no 
longer depicting an eye feature. A sustained wind of 93 kt (107 mph) 
with a gust to 117 kt (135 mph) was reported at the Puerto Cabezas, 
Nicaragua, airport around 03/2139 UTC while the eye of Eta was just 
inland. The initial intensity of 90 kt is based on a standard decay 
rate for inland tropical cyclones.
 
The initial motion estimate is 270/05 kt. The track forecast 
reasoning is fairly straightforward for the next 72 h. A narrow 
ridge to the north and northeast of the cyclone will cause Eta to 
gradually turn toward the west-northwest over the next 12 h, and 
maintain that motion through 48 h. In the 48-72 h period, Eta or its 
remnants are expected to turn northward and then northeastward, and 
emerge over the northwestern Caribbean Sea offshore the Yucatan 
Peninsula by 72 h. Thereafter, the forecast becomes more complex due 
to expected mid-latitude interaction with an upper-level trough/low 
currently over the southwestern U.S. that will be digging 
southeastward and amplifying over the Gulf of Mexico and as far 
south as the Yucatan by 96 h. The trough is expected to lift out Eta 
or its remnants northeastward across Cuba, then slow down and turn 
northward toward the southern Florida peninsula by 120 h when the 
cyclone will be interacting with an upper-level low over the 
southeastern Gulf of Mexico. Due to this complex mid-latitude 
low/trough interaction, the track forecast at days 4 and 5 contains 
some uncertainty. The new NHC track forecast is just a little to the 
left of the previous advisory track through 72 hours, but not as far 
west as the simple- and corrected-consensus models, and is very 
similar to the previous advisory track at 96 and 120 hours.
 
Similar to the track forecast, the intensity forecast is also 
straightforward through 72 h, which calls for Eta to rapidly weaken 
for the next 48 h so using a standard decay rate for inland tropical 
cyclones. By 72 h and beyond, the intensity forecast becomes a 
little more complicated due to the aforementioned mid-latitude 
trough interaction. The global models are still in fairly good 
agreement with the development of an anticyclonically curved 
upper-level jetstream across the northwestern Caribbean Sea, Cuba, 
and the Bahamas by 96 h. There are some subtropical jet dynamics 
already occurring across the northwestern Caribbean, which has 
helped to generate widespread convection across the region today. As 
the jetstream amplifies ahead of the vigorous upper-level trough, 
significant upper-level divergence is expected to develop, which 
will cause surface pressures to fall across the northwestern 
Caribbean Sea. Those strong pressure falls will likely aid in the 
redevelopment of Eta or generate a new tropical cyclone.  Regardless 
of the exact formation, the global and regional models are all in 
good agreement on a tropical or subtropical cyclone developing and 
moving across Cuba and toward Florida on days 4 and 5. The new 
official intensity forecast is very similar to the previous 
intensity forecast through 72 hours, and then is slightly higher 
thereafter, but not as high as some of the intensity guidance like 
the HCCA and ICON consensus models.
 
Key Messages:
 
1. Significant wind damage is expected along the coast of 
northeastern Nicaragua and also inland overnight.
 
2. A dangerous and life-threatening storm surge, along with
destructive waves, are expected along portions of the northeastern
coast of Nicaragua overnight. Water levels could reach as high as 
5 to 10 feet above normal tide levels in some parts of the hurricane
warning area.
 
3. Through Friday evening, heavy rainfall from Eta will lead to
catastrophic, life-threatening flash flooding and river flooding
across portions of Central America, along with landslides in areas
of higher terrain.  Flash and river flooding is also possible across
Jamaica, southeast Mexico, El Salvador, southern Haiti, and the
Cayman Islands.
 
4. Eta is forecast to regain tropical storm strength as it moves
across portions of Cuba and approaches southern Florida this
weekend.  While it is too soon to determine the exact timing,
magnitude, and location of possible impacts from wind and rainfall,
interests in Cuba, southern Florida and the Florida Keys should
monitor the progress of Eta through the week.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/0300Z 13.8N  84.0W   90 KT 105 MPH...INLAND
 12H  04/1200Z 13.9N  84.8W   60 KT  70 MPH...INLAND
 24H  05/0000Z 14.4N  86.4W   35 KT  40 MPH...INLAND
 36H  05/1200Z 15.3N  88.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  06/0000Z 16.0N  89.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  06/1200Z 16.9N  88.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  07/0000Z 17.9N  86.7W   35 KT  40 MPH...OVER WATER
 96H  08/0000Z 21.1N  82.5W   45 KT  50 MPH
120H  09/0000Z 24.3N  80.5W   50 KT  60 MPH
 
$$
Forecaster Stewart
 
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