041
FXUS64 KLCH 200324
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1024 PM CDT Fri Jul 19 2024

...New UPDATE...

.UPDATE...
Issued at 1004 PM CDT Fri Jul 19 2024

Weak frontal boundary continues to sag south across the southern
LA coast. KLCH radar depicts this boundary nicely, with a line of
scattered to numerous showers and storms from near Sabine Pass
east toward Marsh Island. This activity will continue to slide
southward overnight, eventually stalling and expanding in
coverage slightly before spreading back inland during the day
Saturday.

Conditions should stay fairly quiet overnight for inland areas, as
slightly drier midlevel air has nudged southward into the region
in the wake of the front. KLCH 00Z sounding shows PWAT down to 1.8
inches after peaking at almost 2.5 inches at 12Z. Despite this
"front", temperatures are expected to stay close to seasonal
normals tonight with lows in the lower to middle 70s.

Overall, the current forecast is in good shape, but did
make some slight adjustments to hourly PoP/Wx, T and Td grids to
account for recent obs and expected trends. No updates were
needed to text products.

24

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 330 PM CDT Fri Jul 19 2024

Mid-afternoon sfc analysis shows a stationary frontal boundary
draped over the forecast area, with an area of low pressure
spinning near the far nern zones. Water vapor imagery shows the
region remaining under a weakness aloft. Regional 12z soundings
showed plenty of moisture (KLCH PWAT was a ridiculous 2.49 inches)
and nil capping. In response, we saw an area of showers and
thunderstorms develop and push ewd across the area earlier
today...88D imagery shows this activity now east of the
Atchafalaya although widely scattered convection is beginning to
re-fire across mainly ern portions of the area in response to the
low.

Expecting this new round of convection to continue developing
through the afternoon, especially over the nern zones, before
waning with loss of heating. However another round of late night
redevelopment looks on tap courtesy of our typical nocturnal maritime
activity developing and spreading inland.

Thereafter the combination of the lingering weakness aloft, the
meandering sfc boundary and persistent very deep moisture will
maintain elevated rain chances through tomorrow. Forecast
soundings indicate mean RH values around 70 percent and PWAT
values generally between 1.9 and 2.1 inches into Saturday night
(around the 90th percentile per SPC raob climo). WPC is
maintaining the previous highlights of a marginal risk for
excessive rainfall for the forecast area.

The sfc boundary looks to wash out/move out of the area on
Sunday. However the weakness will remain aloft, and a deeper srly
flow is progged to develop which will increase PWAT values in
excess of 2.0 inches area-wide. Along with daytime heating,
widespread showers and thunderstorms are expected to develop, with
again a potential for torrential downpours that may bring about a
localized flood risk

With the widespread cloud cover/precip, heat index values are not
expected to meet advisory criteria at any point during the short
term.

25

&&

.LONG TERM...
(Monday through next Thursday)
Issued at 330 PM CDT Fri Jul 19 2024

A very wet and active work week is in store over the entire longterm
period. The pattern setting up and stalling out will consist of low
pressure trof sitting over the central US with surface high pressure
ridging across the northeast GoM. Weakness aloft combined with a
funneling of moisture off the trof and high pressure will all
combine to bring about widespread showers and thunderstorms each and
every day.

Guidance now brings a series of easterly waves through the western
periphery of the Gulf high, ushering them onshore in central
Louisiana. If this solution is correct, these waves would only
further enhance rainfall rates. Tropical moisture and days of heavy
rainfall will start to push the limits of river and bayou storage,
bringing about the possibility of rising rivers and quickly-
exacerbated flash flooding scenarios. Because of this, WPC has
continued the run of Marginal Risk (1 of 4) for Excessive Rainfall
Monday thru at least Wednesday Morning. While most of us already
have our rain boots and umbrellas at the ready, it`s good to prepare
for the possibility of flash flooding in heavy downpours during
traveling hours next week.

Temperatures will be held well in check Monday through Friday with
most daytime temps topping out in the mid to upper 80s. Muggy
overnight conditions will fall into the low 70s inland to mid 70s
along the coastline.

11

&&

.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Fri Jul 19 2024

Convection continues in the Atchafalaya basin with convection
moving offshore. CAMs keep convection overnight along the coast
with PROB30 for terminals. Overnight winds will be light and
variable with a minimal fog risk.

&&

.MARINE...
Issued at 330 PM CDT Fri Jul 19 2024

Not expecting the need for any headlines on the CWF over the next
several days.

25

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  70  90  71  89 /  10  20  20  70
LCH  75  89  76  88 /  30  60  50  90
LFT  75  91  76  89 /  40  70  40 100
BPT  75  91  75  90 /  30  60  40  90

&&

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

$$

SHORT TERM...25
LONG TERM....11
AVIATION...14