312
FXUS64 KLCH 140942
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
442 AM CDT Tue May 14 2024

...New SYNOPSIS, SHORT TERM, LONG TERM, MARINE...

.SYNOPSIS...
Issued at 425 AM CDT Tue May 14 2024

After a busy past few days, things are finally calming down. KLCH
radar shows the last of the convection over our eastern coastal
waters zones, weakening as it shifts east. The latest WV imagery
and UA analysis shows a pair of vort lobes (the culprits
responsible for the intense storms on Monday) translating along
the north central Gulf coast, on the southeast flank of low
pressure moving toward the mid MS Valley. The main trough axis
extends southward into TX, with a sharp moisture gradient
preceding this axis as drier advects around the base of the
trough.

IR satellite imagery shows quite a bit of high cloudiness
still streaming north over the region, but the back edge of these
clouds are slowly progressing east. As clearing begins, fog
is expected to develop and increase in coverage amid the light
winds and saturated soils, with periods of dense fog anticipated.
A Dense Fog Advisory has been issued for our SE TX Counties.

The passage of the convection has left a relatively cooler airmass
over the region with temperatures in the middle 60s to around 70
early this morning.

24

&&

.SHORT TERM...
(Today through Thursday night)
Issued at 425 AM CDT Tue May 14 2024

A weak cool front will move east across the area this morning,
with winds becoming westerly ushering in a drier airmass. Skies
are expected to clear today as PWAT values fall below an inch and
midlevel rh drops to around 20% or less. Weak ridging aloft and
surface high pressure will transit across the area through
Wednesday, providing a very nice and much needed break from the
recent wet weather. With the drier airmass in place and sufficient
insolation expected, temperatures today and Wednesday should
easily warm into the middle to upper 80s each afternoon, with
highs likely topping out around 90 Wednesday. Overnight lows are
expected to fall just a bit below seasonal normals, with minimums
ranging from around 60 across central LA to the middle 60s along
the I-10 corridor. Patchy to areas of fog will again be possible
tonight as winds lighten.

The dry break will unfortunately be short-lived as the surface
high slides east and another shortwave trough moves into the SW US
late Wednesday. A warm and moist advection regime will develop as
the LLJ strengthens across TX and translates east Wednesday night
into Thursday. Showers and storms will develop across TX
Wednesday night and spread east across our area on Thursday, with
PoPs sharply ramping up during the day. Another heavy rain
scenario will develop as PWATs climb back up to 2 inches or
higher within an environment marked by increasing instability and
deep layer shear. Most guidance members have been indicating the
potential for elevated QPF across portions of the area, although
there are some discrepancies regarding placement. A general
consensus, supported by NBM probabilistic guidance, suggests that
these higher totals could fall across interior SE TX again, which
unfortunately is one of the hardest hit regions in recent weeks.
In collaboration with WPC, a Moderate Risk for excessive rainfall
has been introduced for Day 3 (Thursday) for areas along/north of
I-10, with a Slight Risk further south. Some adjustments to the
outlook can be expected as the event approaches.

While the heavy rainfall and flood risk are the primary concern
with this system, there is a non-zero potential for severe weather
as well. The latest SPC outlook has a Marginal Risk in place for
Thursday, with the expectation that convection that forms across
portions of central TX will evolve into a linear mode as it moves
east toward SE TX/SW LA. While all modes of severe weather will be
possible, the primary threats will be from isolated damaging wind
gusts and large hail.

24

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 425 AM CDT Tue May 14 2024

Ongoing, potentially heavy, precipitation will start the extended
period Friday as a series of upper level disturbances cross the
northern gulf coast as they wrap around a broader shortwave moving
across the southern plains. This energy will continue to take
advantage of abnormally high forecast PWAT values near or above 2
inches to produce high rainfall rates falling on already saturated
grounds. Thus, the risk for flash flooding will continue through
Friday evening.

Precip looks to finally end sometime late Friday evening or early
Saturday morning with the passage of a weak frontal boundary. While
there will be no appreciable change in surface airmass behind the
front, it will scour out most of the moisture aloft. There remains
some inter-model variation regarding the timing of the fropa, but
better agreement compared to 24 hours ago. Guidance continues to
maintain isolated PoPs through the day Saturday for account for
wraparound moisture. Maintained isolated wording for now, but
thinking that there is unlikely to be enough moisture left behind
the front for this to be much of a concern. Clearing skies and
surface high pressure building into the region will allow for
temperatures to climb to near 90 each afternoon Saturday through
Monday with a more extended period of drier weather looking to set
up next week.

Jones

&&

.AVIATION...
(00Z TAFS)
Issued at 604 PM CDT Mon May 13 2024

Severe thunderstorm cluster hitting LFT now and ARA within the
next half hour. LFT just gusted to 69 kt or 79 mph, expect
something similar for ARA within a few minutes. Remainder of
forecast will see MVFR ceilings overnight, with MVFR visibility
possible for southern sites between 10-14z. Improving conditions
expected for Tuesday.

08/DML

&&

.MARINE...
Issued at 425 AM CDT Tue May 14 2024

West to northwest winds are expected today with the passage of a
weak cold front. Winds will shift northerly tonight then back east
to southeast through the day Wednesday as high pressure quickly
slides east. Onshore flow will then persist, strengthening
slightly, through the end of the week. Exercise caution conditions
will be possible at times. Shower and thunderstorm chances will
return Thursday as another low pressure system approaches the
area.

24

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  85  60  89  64 /   0   0   0   0
LCH  86  65  89  69 /   0   0   0  10
LFT  88  66  91  69 /   0   0   0   0
BPT  88  65  89  70 /   0   0   0  10

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...Dense Fog Advisory until 8 AM CDT this morning for TXZ180-201-
     259>262-515-516-615-616.

GM...None.
&&

$$

SHORT TERM...24
LONG TERM....66
AVIATION...08