[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 110859
TCDAT4

Tropical Storm Eta Discussion Number  44
NWS National Hurricane Center Miami FL       AL292020
400 AM EST Wed Nov 11 2020

Eta has become better organized over the past few hours, with a
better-defined eye feature on the Key West radar.  Satellite
pictures also show a more symmetric presentation and a large
cluster of deep convection near the center.  Radar data has shown
increasing wind speeds in the mid-levels, which supports
conservatively raising the initial wind speed to 60 kt.  The
current position is southwest of the eye feature on radar, assuming
some shear remains, but a NOAA Hurricane Hunter aircraft is
scheduled to be in the storm in a few hours to acquire better data
on both the initial position and intensity.

It appears that the center of Eta has re-formed to the north-
northeast tonight, so an initial motion is hard to determine,
but is estimated to be northward at about 10 kt.  Remarkably, model
guidance has become well clustered just east of the previous
forecast track as it seems apparent that Eta will now recurve
around the ridge toward the Florida Big Bend region and out into
the western Atlantic Ocean.  The biggest change is that the models
are faster than before, and the official forecast follows that
lead, along with a small eastward forecast adjustment, near or just
east of the model consensus.

Further strengthening is possible today while the shear remains
low-to-moderate.  However, all of the models do show increasing
shear by tonight, and the NHC forecast continues to call for
weakening of Eta as it approaches the west coast of Florida.
However, it would take only a small forecast error to allow Eta to
come ashore as a hurricane, and hence a Hurricane Watch has been
issued this morning.  Rapid weakening is anticipated once Eta makes
landfall, and strong shear should prevent any regeneration over the
western Atlantic Ocean. The new forecast is a little higher than
the previous advisory, mostly due to current trends, and is closer
to the more bullish HMON and HWRF models.

Key Messages:

1. Life-threatening storm surge is possible early Thursday along
portions of the Florida Gulf Coast from Bonita Beach to
Steinhatchee River, including Tampa Bay and Charlotte Harbor.
Residents in this area should follow any advice given by local
officials.

2. Hurricane-force winds are possible along portions of the west
coast of Florida from Anna Maria Island to Yankeetown by early
Thursday. Tropical-storm-force winds are expected by late Wednesday
along portions of the Florida Gulf Coast from Bonita Beach to
Suwanee River, and are possible Thursday from Suwannee River to
Aucilla River. Interests elsewhere along the Florida Gulf Coast
should monitor the progress of Eta, as additional watches and
warnings may be needed today.

3. Heavy rainfall from Eta will continue across western Cuba and
South Florida and spread northward across portions of West and North
Florida Wednesday through Friday. Additional flash and urban
flooding will be possible in South Florida on Wednesday, especially
across previously inundated areas, and across portions of West
Florida through Friday.


FORECAST POSITIONS AND MAX WINDS

INIT  11/0900Z 25.0N  84.1W   60 KT  70 MPH
 12H  11/1800Z 26.4N  83.9W   65 KT  75 MPH
 24H  12/0600Z 27.9N  83.4W   60 KT  70 MPH
 36H  12/1800Z 29.2N  82.6W   45 KT  50 MPH...INLAND
 48H  13/0600Z 30.2N  81.2W   30 KT  35 MPH
 60H  13/1800Z 30.9N  79.5W   30 KT  35 MPH
 72H  14/0600Z 31.0N  78.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  15/0600Z...DISSIPATED

$$
Forecaster Blake
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