734
FXUS64 KLCH 241217
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
617 AM CST Tue Dec 24 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday night)
Issued at 440 AM CST Tue Dec 24 2024

Here we are, the night before Christmas (and the first day of the
Festival of Lights!) and all through the WFO, keyboards are
a-tapping away with the holiday forecast. Hopefully Rudolph has
shined his nose so it`s nice and bright; Santa will need all the
help he can get to navigate the US tonight!

Widespread cloud cover has enveloped much of Louisiana, which
spread east from Texas where a frontal system is preparing to
march east today. Already a few showers are developing in
southeast Texas along the warm sector moving inland. Expect this
showery activity to continue into lunchtime. As CAPE slowly
increases today, a few storms will be possible across wrn portions
of the forecast area. Louisiana should largely stay dry until
later in the afternoon and evening. A cluster of convection
associated with cold front extending southwest across Texas will
skate down into southeast Texas late tonight, arriving to
Louisiana around midnight. The greatest threat will be for strong
gusty winds with the line. Guidance is unsure how far east it will
extend into Louisiana before sliding off of the coastline.
Considering the corridor of greatest CAPE should exist along an
axis across Galveston, there is confidence the line will weaken
and slip offshore before moving as far east as Lafayette.

Nevertheless, public across southeast Texas and southwest and
central Louisiana should have a way to receive severe alerts
before settling in for the evening.

The trof aloft spawning the frontal system outruns the front
Christmas (Wednesday) morning and the front stalls in east Texas.
A weak surface trof swinging over southeast Texas could help to
continue spreading showers and a few isolated thunderstorms over
the region into Christmas Day.

Another much stronger trof develops on Christmas, amplifying with
a slightly negative tilt as it nears the forecast area Thursday.
Another renewed slug of moisture is pulled northward ahead of this
trof to combine with 50 to 60 knots of bulk shear spreading over
areas primarily along and north of I-10 and west of I-49. The
shear suggests at least a brief period that rotating super cell
type storms could be supported; so long as CAPE is sufficient.
Forecast guidance indicates greatest ML CAPE could be contained to
the coastline, however if this energy pool moves inland, the
severe threat will exist where it goes. Where these two
parameters can mix, organized thunderstorms are likely. Thus, due
to the risk, the SPC has placed the Lakes region into a Slight
Risk (2 of 5) of severe weather and all remaining areas west of
lower Acadiana in a Marginal Risk (1 of 5) for Thursday afternoon
and evening. The greatest risk will be along and north of I-10
and west of I-49, where highest shear will be, but lesser shear
and CAPE could still produce severe storms across southwest, south
and central Louisiana, thus all shareholders should be mindful of
the forecast Thursday. The primary hazards will be damaging wind
gusts; hail and isolated tornadoes cannot be ruled out.

Warm temperatures above normal will begin today and will continue
into the longterm period. Highs from 70 to the lower 70s can be
expected today through Thursday.

11/Calhoun

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 440 AM CST Tue Dec 24 2024

Once again, the active weather pattern continues into the longterm
period on Friday with widespread showery activity ongoing at 12z.
A shortwave perturbation is expected to pass overhead into Friday
morning. By the start of the period it should be long beyond the
Ozarks plateau, releasing convection over the CWA from its
forcing. This will result in a lull of showery activity throughout
the day.

The next shortwave trof starts to amplify on Saturday with a
renewed influx in moisture off of the Gulf. This moisture will
allow for a new round of convection to develop across primarily
southwest and central Louisiana (moisture intrusion into Texas
isn`t great enough before the trof and shear arrive). A brief
threat of organized cells with a risk of wind damage may develop
during the afternoon.

Also, with every wave of convection, the ground will become
further saturated, increasing the flash flood risk each day. Fcst
PWAT values are well within the 50th percentile for this time of
year, thus any one passing wave may not have a specific flood
risk. However, compounding rainfall could result in quickly
exacerbated flood conditions in urban centers and low lying areas.

No break in the above-average daytime temperatures is on the
horizon. Low to mid 70s with high humidity can be expected through
the longterm period and end of the year.

11/Calhoun

&&

.AVIATION...
(12Z TAFS)
Issued at 541 AM CST Tue Dec 24 2024

A thick moisture layer is moving onshore ahead of an approaching
frontal system. CIGs are holding steady in the 4.5 to 10 kft layer
as a small dry layer exists below this point. Guidance keeps
clouds above 5 kft for much of the period, until after 23z when
sun sets and showers begin moving in from the west. Thereafter,
ceilings drop swiftly to 1000 feet and less thru 12z.

A few showers are spreading over southeast Texas within the
advancing warm sector. Vicinity showers will likely be present
near BPT for much of the day, with vicinity thunderstorms
beginning to develop and spread east to LCH and AEX after 21z.

Confidence is low that showers will spread inland at LFT and ARA
in this forecast period.

Periods of scattered showers and isolated thunderstorms will
prevail over western terminals through the early evening. The
front moving into east Texas will send a complex of thunderstorms,
some severe, towards southeast Texas after sundown. Highest CAPE
should be present near Galveston which should cause the cluster to
push south into the west Gulf. Southwest terminals should still
receive some impacts from line, which could arrive to BPT and LCH
terminals as early as 06z or as late as 10z. When it does move
through, expect gusty winds, frequent lightning and visibility-
reducing rains. AEX could receive some impacts from the line,
depending on how much of it pushes into central LA. Impacts
should be less than those mentioned for BPT/LCH.

Somewhat elevated winds will prevail from the east-southeast to
southeast ahead of the front. BPT could see some gusts as the
pressure gradient tightens.

11/Calhoun

.MARINE...
Issued at 440 AM CST Tue Dec 24 2024

Elevated onshore flow develops today ahead of an approaching
frontal system. A few isolated showers and thunderstorms will be
possible over southeast waters today, but a stronger push of
showers and thunderstorms is expected to move across coastal
waters around midnight tonight. Some storms could be strong to
severe with lightning and gusty winds as primary hazards. An
active jet stream will keep elevated onshore winds and scattered
to numerous showers in the forecast each day from Christmas to
the end of the week.

Although conditions could be hazardous due to convection, winds
and seas are anticipated to remain below Small Craft Advisory
criteria throughout the forecast period.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  70  51  68  56 /  10  40  60  30
LCH  71  56  70  58 /  10  50  60  20
LFT  72  56  71  60 /   0  30  70  30
BPT  72  59  71  59 /  30  60  60  10

&&

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

$$

SHORT TERM...11
LONG TERM....11
AVIATION...11