Severe Thunderstorm Warning 219, NWS Lake Charles, LA

Area Forecast Discussion
National Weather Service Lake Charles LA
1145 AM CST Mon Nov 20 2023

...New AVIATION...

.SHORT TERM...
(Today through Wednesday night)
Issued at 501 AM CST Mon Nov 20 2023

NW to SE oriented WMFNT stretching from roughly KJAS to KLCH and
then near/along the coast is yielding a distinct MSTR gradient
across the area this morning, with SFC dewpoints in the mid 60s over
SE TX and the mid/upper 40s across east central LA.  These values
will continue to rise through the day as the warm front retreats
northward amid increasing southerly flow downstream of an
approaching upper trof and associated SFC low/trailing CDFNT. Along
with warming SFC temperatures (highs reaching the mid to upper 70s),
this will yield a thermodynamic profile characterized by modest CAPE
(~2k J/kg) by this afternoon/early evening.  Meanwhile,
strengthening kinematic fields will result in 0-6km bulk shear of 60-
70KT and 0-1km SRH 100-200 m2/s2. As forcing for ascent increases
with the approaching trof, scattered showers and thunderstorms are
forecast to develop late morning to early afternoon, initially
across SE TX, then further east as the afternoon progresses. CAMs
generally depict more of a cellular rather than linear mode across
our area, though the latter will become more prevalent late this
evening as convection pushes east of our area. Best juxtaposition
of these ingredients and lift will reside across Central LA,
roughly coincident with the SPC enhanced risk area.

Convection will end from west to east as the cold front pushes
through the area this evening, with activity expected to be out of
the area shortly after midnight. Brisk north winds will begin usher
in a much cooler airmass behind the front, with CAA continuing
through the day on TUE.  Cloud cover will linger across the area,
however, as the southern portion of the upper trof cuts off
leaving the area underneath a moist SW flow aloft. Cloudy and cool
will continue on WED.

13

&&

.LONG TERM...
(Thursday through Monday)
Issued at 501 AM CST Mon Nov 20 2023

As mentioned above, the southern portion of the upper trof is
progged to eject out across the NW Gulf Coast region in the THU-
FRI time period, but there are some differences in how this
feature is handled by the global models. The NBM is quite
aggressive in bringing PoPs back to the area, but for this
cycle have scaled them back closer to the previous forecast. Dry
and cool is expected FRI and SAT, with another upper trof bringing
rain chances back SUN and MON.

13

&&

.AVIATION...
(18Z TAFS)
Issued at 1113 AM CST Mon Nov 20 2023

Ceilings over SETX/SWLA are gradually lowering into the midday
hours across the area with SCT/BKN decks varying between 2000ft
and 7000ft where low level clouds are fewer. Scattered
Thunderstorms are developing over eastern TX with a NNE motion. Overall
BKN to periodic OVC decks will become more prevalent into the
afternoon hours and evening. VFR/MVFR conditions will periodically
deteriorate to IFR or LIFR as VCTS / TSRA begins over western
sites shift east. A series of scattered / broken lines of
thunderstorms will continue lifting from the SW to the NE while
the overall storm pattern gradually shifts eastward throughout the
afternoon / evening hours. Strong low to mid level directional
wind shear in place will help facilitate severe thunderstorms
containing hail, damaging low level gusts. Potential for Tornadoes
does exist through the early evening hours before exiting the LCH
CWA eastern sites by Midnight moving into Tuesday morning.

&&

.MARINE...
Issued at 501 AM CST Mon Nov 20 2023

Winds and seas will increase on today, along with the chance of
showers and thunderstorms, as a surface low deepens over the
southern plains and moves just north of the area. The passage of a
cold front tonight will bring strong and gusty north winds that
will persist through Wednesday morning, and Small Craft
Advisories will likely be needed. Offshore flow will gradually
diminish through the rest of the week.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  51  60  42  59 /  70  10  10  10
LCH  54  62  47  59 /  50   0  10  10
LFT  59  64  49  60 /  80  10  10  10
BPT  54  64  47  61 /  30   0   0  10

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&

SHORT TERM...30
LONG TERM....30
AVIATION...30