[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 120246
TCDAT4

Tropical Storm Eta Discussion Number  47
NWS National Hurricane Center Miami FL       AL292020
1000 PM EST Wed Nov 11 2020

Deep convection intensified over the northern portion of the
circulation of Eta over the past few hours, however the overall
cloud pattern has not become better organized this evening.
Adjusted flight-level and SFMR-observed surface winds from an Air
Force Reserve Hurricane Hunter aircraft indicate that the maximum
winds are near 55 kt, with the central pressure holding about
steady for now.  Since the storm will be moving over progressively
cooler waters, with strong west-southwesterly shear and some
incursions of drier air, gradual weakening is likely up to landfall
tomorrow morning.  A more rapid weakening is likely after the center
crosses the coast tomorrow.  The dynamical guidance does not
indicate significant restrengthening after Eta emerges into the
Atlantic within 24 hours, although some baroclinic forcing could
allow the system to maintain its intensity for awhile.  The
cyclone is likely to be absorbed by a frontal zone in 60-72 hours if
not sooner.

Center fixes indicate that the motion continues to be just a little
to the east of due north, or 010/10 kt.  A slight turn toward the
right is expected soon, and over the next couple of days Eta should
move north-northeastward to northeastward, ahead of a broad
mid-level trough, until dissipation.  The official track forecast
follows the general trajectory of the simple and corrected
dynamical model consensus, but is somewhat slower than the consensus
guidance in deference to the latest GFS prediction.


Key Messages:

1. There is a danger of life-threatening storm surge along portions
of the Florida Gulf Coast from Bonita Beach to the Suwannee River,
including Tampa Bay and Charlotte Harbor.  Residents in this area
should follow any advice given by local officials.

2. Tropical-storm-force winds are expected tonight and early
Thursday along portions of the Florida Gulf Coast from Bonita Beach
to the Suwanee River, and are possible tonight on Thursday from the
Suwannee River to the Aucilla River.  Interests elsewhere along the
Florida Gulf Coast should monitor the progress of Eta.

3. Heavy rainfall from Eta will continue to spread northward across
West and Central Florida through Thursday. Additional flash and
urban flooding will be possible in South Florida through Thursday,
especially across previously inundated areas.  Flash, urban, and
isolated minor river flooding is expected across portions of West
and North Florida through Thursday.


FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 28.3N  83.4W   55 KT  65 MPH
 12H  12/1200Z 29.7N  82.4W   40 KT  45 MPH...INLAND
 24H  13/0000Z 31.8N  79.8W   35 KT  40 MPH...OVER WATER
 36H  13/1200Z 33.7N  76.3W   30 KT  35 MPH
 48H  14/0000Z 35.5N  72.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  14/1200Z 37.0N  68.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  15/0000Z...DISSIPATED

$$
Forecaster Pasch
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