[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 150235
TCDAT4

Tropical Depression Nicholas Discussion Number  12
NWS National Hurricane Center Miami FL       AL142021
1000 PM CDT Tue Sep 14 2021

Satellite imagery, radar data, and surface observation indicate
that the center of Nicholas is over the Beaumont/Port Arthur area
of southeastern Texas.  The cyclone is currently comprised of a
large swirl of low- to mid-level clouds and showers, with a few
patches of deep convection well removed from the center.  The
initial intensity of 30 kt is based on a combination of Doppler
radar data and surface obs, and these winds are mainly over water
to the southeast of the center.  Nicholas should continue to weaken
due to strong shear, dry air entrainment, and land interaction,
and the cyclone is forecast to degenerate to a remnant low after 24
h and dissipate completely by 72 h.  It should be noted that some
of the track guidance models show enough south of east motion to
bring the center back over the Gulf of Mexico in a day or two.
However, even if this should occur the shear and dry air should
prevent any re-development.

The initial motion is 060/5.  While there is some spread in the
guidance, it generally agrees on a slow eastward motion for 36 h
or so, followed by a northward drift.  The new forecast track has
only minor changes from the previous track.

Although the winds associated with Nicholas are subsiding, due
to the forecast slow motion, heavy rainfall and a significant flash
flood risk will continue along the Gulf Coast for the next couple
of days.

The is the last advisory on Nicholas issued by the National
Hurricane Center.  Future information on this system can be found in
Public Advisories issued by the Weather Prediction Center beginning
at 4 AM CDT, under AWIPS header TCPAT4, WMO header WTNT34 KWNH, and
on the web at http://www.wpc.ncep.noaa.gov.


Key Messages:

1. Heavy rainfall will impact areas across southern and central
Louisiana, southern Mississippi, far southern Alabama, and the
western Florida Panhandle through early Friday. Significant rainfall
amounts are expected, potentially resulting in areas of
life-threatening flash and urban flooding across these areas.
Widespread minor to isolated moderate river flooding is also
possible.

2. Storm surge inundation along the coasts of upper Texas and
southwestern Louisiana will diminish tonight.

3. Wind gusts to tropical-storm force are possible for a few more
hours along portion of the Louisiana and upper Texas coasts.


FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 30.0N  94.1W   30 KT  35 MPH
 12H  15/1200Z 30.2N  93.6W   25 KT  30 MPH...INLAND
 24H  16/0000Z 30.2N  92.9W   25 KT  30 MPH...INLAND
 36H  16/1200Z 30.4N  92.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  17/0000Z 30.9N  92.6W   15 KT  15 MPH...POST-TROP/REMNT LOW
 60H  17/1200Z 31.5N  92.6W   15 KT  15 MPH...POST-TROP/REMNT LOW
 72H  18/0000Z...DISSIPATED

$$
Forecaster Beven
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