[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 020850
TCDAT4

Hurricane Eta Discussion Number   7
NWS National Hurricane Center Miami FL       AL292020
400 AM EST Mon Nov 02 2020

Eta has continued to become better organized, with a distinct
Central Dense Overcast surrounded by many banding features.  A
low-level eye feature was seen in GPM Microwave Imager data, and
Dvorak intensity estimates are at 65 kt from both TAFB and SAB.
Based on this, the system is upgraded to a hurricane.  Continued
strengthening is likely, given the very high oceanic heat content
and only moderate easterly vertical shear.  The official forecast
calls for rapid intensification, in line with the SHIPS Rapid
Intensification Index which shows a 48 percent chance of a 30 kt
increase over 24 hours.  Although not explicitly shown, Eta could
very well be a 100-kt major hurricane when it crosses the coastline.
After landfall, weakening will occur while the cyclone interacts
with the very mountainous terrain of Central America.  Even though
official forecast points are shown through day 5, it is doubtful
that the surface circulation could survive after being inland that
long over the mountains of Nicaragua and Honduras.  Although some
of the global models are showing a cyclone over the northwestern
Caribbean later this week and into the weekend, it is not certain
whether this is Eta, or a new system that could form in that area.

The hurricane is moving westward, or at about 265/10 kt.  The track
forecast philosophy remains basically unchanged.  For the next few
days, Eta should move westward or west-southwestward to the south
and southeast of a mid-tropospheric high pressure system centered
near the western Gulf of Mexico coast.  The official track
forecast is nearly identical to the previous one, and also very
similar to the various model consensus predictions.

Since this is likely to be a very slow-moving system after it makes
landfall in Central America, torrential rains and flooding will be
a major threat from Eta.


Key Messages:

1. Eta is forecast to continue to strengthen, and it could become a
major hurricane before it reaches the northeastern coast of
Nicaragua early Tuesday, where a Hurricane Warning is in effect.  A
Tropical Storm Warning is in effect for a portion of the
northeastern coast of Honduras.

2. 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.

3. A life-threatening storm surge, along with damaging waves, is
expected along portions of the northeastern coast of Nicaragua near
and to the north of where the center makes landfall.  Water levels
could reach as high as 10 to 15 feet above normal tide levels in
some parts of the hurricane warning area. Preparations to protect
life and property should be rushed to completion.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 14.8N  80.9W   65 KT  75 MPH
 12H  02/1800Z 14.6N  82.0W   80 KT  90 MPH
 24H  03/0600Z 14.2N  83.0W   95 KT 110 MPH
 36H  03/1800Z 14.0N  83.7W   85 KT 100 MPH...INLAND
 48H  04/0600Z 13.9N  84.5W   45 KT  50 MPH...INLAND
 60H  04/1800Z 14.0N  85.7W   30 KT  35 MPH...INLAND
 72H  05/0600Z 14.4N  86.9W   25 KT  30 MPH...INLAND
 96H  06/0600Z 15.2N  88.6W   25 KT  30 MPH...INLAND
120H  07/0600Z 15.8N  88.8W   20 KT  25 MPH...INLAND

$$
Forecaster Pasch
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