[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 071501
TCDAT4

Tropical Storm Eta Discussion Number  28
NWS National Hurricane Center Miami FL       AL292020
1000 AM EST Sat Nov 07 2020

Satellite imagery and surface data indicate that Eta has become a
little better organized this morning, with the center re-forming to
the northeast near an area of deep convection.  Surface
observations from Grand Cayman Island show that the system has
regained tropical-storm strength, and the initial intensity is
increased to 35 kt.

The initial motion is uncertain dur to the reformation, with the
best estimate of 055/15.  This general motion should continue for
the next 24 h or so as Eta is steered by a mid- to upper-level
trough over the Gulf of Mexico.  From 24-96 h, the trough is
forecast to become a cut-off low, and Eta is expected to turn
northward, northeastward, and eventually westward as it merges with
the low.  There remains some spread in the guidance in just where
these turns will occur and how close the center will come to south
Florida and the Florida Keys.  This part of the new track is nudged
just a little north of the previous track.  After 96 h, Eta should
move slowly across the eastern Gulf of Mexico, with the forecast
track showing a northward motion as a compromise of the
poorly-agreeing guidance.

Although the storm is experiencing moderate to strong southwesterly
shear, strong upper-level divergence caused by the trough should
allow strengthening through about 48 h, although the cyclone may
acquire some subtropical characteristics as it merges with the
baroclinic system.  After that time, dry air entrainment is likely
to cause Eta to slowly weaken through the remainder of the forecast
period.  The new intensity forecast is unchanged from the old
forecast.

The new forecast track requires a Tropical Storm Warning for south
Florida and the Florida Keys at this time.

Key Messages:

1. Heavy rainfall will continue across the Cayman Islands, portions
of Cuba and Jamaica, and will spread north into the Bahamas and
southern Florida. This rain may result in significant,
life-threatening flash flooding and river flooding in Cuba. Flash
and urban flooding will also be possible for the Cayman Islands,
Jamaica, the Bahamas and southern Florida.

2. Tropical storm conditions are expected today and Sunday in
portions of the Cayman Islands, Cuba, and the northwestern Bahamas,
where a Tropical Storm Warning is in effect.

3. Tropical storm conditions are expected by late Sunday in the
Florida Keys and along portions of the southeast Florida coast,
where a Tropical Storm Warning is in effect. Tropical storm
conditions are possible elsewhere in portions of southern and
central Florida beginning Sunday night, where a Tropical Storm Watch
is in effect. Additional Tropical Storm Warnings will likely be
needed later today.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 19.6N  81.8W   35 KT  40 MPH
 12H  08/0000Z 20.8N  80.6W   40 KT  45 MPH
 24H  08/1200Z 22.5N  79.5W   45 KT  50 MPH...INLAND
 36H  09/0000Z 23.8N  79.3W   50 KT  60 MPH...OVER WATER
 48H  09/1200Z 25.0N  80.1W   55 KT  65 MPH
 60H  10/0000Z 25.8N  81.9W   55 KT  65 MPH
 72H  10/1200Z 26.2N  83.2W   50 KT  60 MPH
 96H  11/1200Z 26.5N  84.0W   45 KT  50 MPH
120H  12/1200Z 28.5N  84.0W   40 KT  45 MPH

$$
Forecaster Beven
This weather bulletin was brought to you by:
www.nashvilleweather.net