[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 082054
TCDAT2

Tropical Storm Nicole Discussion Number   7
NWS National Hurricane Center Miami FL       AL172022
400 PM EST Tue Nov 08 2022

Satellite imagery indicates that the central convection associated
with Nicole has become better organized this afternoon, with a
curved convective band wrapped about three-quarters of the way
around the center.  An earlier scatterometer overpass showed winds
near 45 kt about 60 n mi northwest of the center, and a just
received microwave overpass shows an additional increase in
organization.  Based on these data, the initial intensity is
increased to 55 kt. Water vapor and air mass imagery shows a large
area of mid- to upper-level dry air over the southern semicircle of
the circulation, and some of this may be entraining into the core at
this time.

Nicole is continuing its anticipated turn with the initial motion
now 260/9.  A strong deep-layer ridge over the eastern United
States should steer the storm west-southwestward during the next
24-30 h, with this motion bringing the center near or over the
Northwestern Bahamas.  After that time, the ridge is forecast to
shift eastward allowing Nicole to turn westward to
west-northwestward as it approaches the east coast of Florida.
There is some spread in the guidance as to how much of a turn will
occur, with the ECMWF and GFS showing a more westward motion, while
the HWRF and HMON show a more northwestward motion.  This part of
the forecast track is along the south edge of the guidance and
agreement with the ECMWF and UKMET. After landfall in Florida,
Nicole should turn generally northwestward, with the center
forecast to pass near or over the west coast of Florida north of
Tampa by about 48 h.  This should be followed by a turn toward the
north and northeast through the eastern United States as the cyclone
recurves on the east side of a large baroclinic trough moving
through the central United States.  This part of the forecast track
is closer to the various consensus models, and overall the new
forecast track is a little south of the previous track through 60 h
and a little west of the previous track after that time.

Nicole will be traversing relatively warm SSTs of 27-28 degrees
Celsius and upper-level conditions, while not ideal due to a nearby
upper-level trough, are expected to allow some strengthening before
the cyclone reaches Florida. The new intensity forecast follows the
previous forecast and calls for Nicole to become a hurricane when it
is near the northwest Bahamas and remain a hurricane when it reaches
Florida.  This part of the intensity forecast is at the high end of
the intensity guidance. Weakening is expected after Nicole moves
inland over Florida and while it accelerates northeastward over the
southeastern United States.  Extratropical transition is expected
to start between 60-72 h and be complete by 96 h, with the storm
likely to maintain gale-force winds after transition.  The cyclone
is expected to dissipate as it merges with another mid-latitude low
pressure area by 120 h.


Key Messages:

1. Hurricane conditions and a dangerous storm surge are expected in
portions of the northwestern Bahamas on Wednesday, where a Hurricane
Warning is in effect.

2.  Hurricane conditions are expected across portions of the coast
of southeast and east-central Florida beginning late Wednesday or
Wednesday night, where a Hurricane Warning is in effect.  Tropical
storm conditions are expected in the Tropical Storm Warning
areas in Florida and Georgia beginning early Wednesday.

3. A dangerous storm surge is expected along much of the east coast
of Florida and portions of coastal Georgia where a Storm Surge
Warning is in effect.  The storm surge will be accompanied by large
and damaging waves.  Residents in the warning area should listen to
advice given by local officials.

4. Do not focus on the exact track of Nicole since it is expected to
be a large storm with hazards extending well to the north of the
center, outside of the forecast cone. These hazards are likely to
affect much of the Florida peninsula and portions of the southeast
United States.

5. Nicole will produce heavy rainfall Wednesday and Thursday across
the Florida Peninsula. Flash and urban flooding will be likely
across portions of the Florida Peninsula along with possible renewed
river rises on the St. Johns River. On Friday and Saturday, flash,
urban and small stream flooding will be possible in the Southeast
through the Mid-Atlantic and central Appalachians.


FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 27.5N  73.7W   55 KT  65 MPH
 12H  09/0600Z 27.0N  75.2W   60 KT  70 MPH
 24H  09/1800Z 26.7N  77.2W   65 KT  75 MPH
 36H  10/0600Z 27.2N  79.9W   65 KT  75 MPH
 48H  10/1800Z 28.6N  82.4W   55 KT  65 MPH...INLAND
 60H  11/0600Z 31.2N  83.4W   40 KT  45 MPH...INLAND
 72H  11/1800Z 34.7N  81.9W   35 KT  40 MPH...INLAND
 96H  12/1800Z 45.0N  71.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  13/1800Z...DISSIPATED

$$
Forecaster Beven
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