820
FXUS64 KLCH 012333
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
633 PM CDT Thu Oct 1 2026

...New AVIATION...

.KEY MESSAGES...

-Rain chances will be increasing into the weekend as an upper level
 ridge will be replaced with an upper level trough and a surface
 boundary.

-There will be an increase in the potential for heavy rainfall
 over the weekend as the upper level trough and frontal system
 meet up with tropical moisture and slowly move across.

-A secondary surface front on Monday will bring lower rain chances
 and slightly cooler temperatures closer to the climo norm for
 early next week.

&&

.DISCUSSION...
(This evening through next Wednesday)
Issued at 226 PM CDT Thu Oct 1 2026

Latest upper air analysis shows height falls across the region as
the upper level ridge that has been overhead continues to weaken.
Meanwhile, an upper level low is opening up as it moves into the
Southern Plains with a stream of tropical East Pacific moisture
ahead of it. Also, a surge of rich moisture from the northwest
Caribbean is moving up into the Gulf between an upper level low over
the Yucatan and and an upper level ridge east of Florida.

With the weakening upper level ridge, moisture values at increasing
with the latest upper air data and Goes sounding showing PWAT now
over 2 inches. Southerly flow allowing for very warm above normal
temperatures. Shower activity has developed with the daytime heating
and this activity is expected to decrease by sunset.

Overnight into Friday, very moist air mass will be in place creating
hot and muggy conditions. Nocturnal shower activity will move
onshore before daybreak with an increase in showers and
thunderstorms in the afternoon, again decreasing after sunset.

Over the weekend there will be the potential for heavy rainfall with
some flood risk. The upper level trough from the open upper level
low will push eastward, also moving a surface front into the
forecast area on Saturday. Meanwhile, the East Pac tropical moisture
and the deep rich moisture from the Caribbean will merge into the
region ahead of the trough and frontal boundary. The weakness aloft,
and any daytime heating, will work with the deep moisture to produce
widespread showers and a few thunderstorms during the afternoon into
evening.

A very highly anomalous atmosphere is expected for Saturday into
Sunday. Consensus of the guidance shows precipitable water values
between 2.3 and 2.5 inches, with the high end guidance depicting
PWAT up to 2.7 inches. These values are well above the 90th
percentile climo value of 1.94 inches and at or above the max moving
average and daily climo max. The 100H-50H mean layer relative
humidity will be over 80 percent, and with warm cloud layers
projected to be around or above 15k feet depicting good warm rain
processes for the convection, the activity that develops will
have the potential to be highly efficient precipitation producers,

The question is still how widespread for any heavy rain and the
timing. That will depend on the lift associated with the upper level
trough and surface frontal boundary, and how much instability
develops. At this time, the best lift and instability is noted from
Saturday afternoon into early Sunday morning as the surface frontal
boundary moves through. Still, the overall guidance is depicting the
strongest lift to be just offshore and into southeast Louisiana.
That may limit the strength of the showers and storms. however
projected CAPES are still in the 1500 to 2000 j/kg range.

Therefore, this situation still needs to be respected with the
copious amounts of tropical moisture. The forecasted rainfall total
amounts through Sunday are averaging between 1.5 and 2.75 inches,
with the highest amounts for the southeast portion of the forecast
area. Meanwhile, 90th percentile or the reasonable highest amounts
are in the 2.5 to 4.5 inch range. Therefore, a Slight Risk (level 2
out of 4) Potential or between a 15 and 25 percent chance of seeing
excessive rainfall that may lead to flash flooding will be outlined
for much of the forecast area for Saturday with a Marginal Risk
extending into Sunday. At the very least, there is above an 80
percent chance of seeing a wetting rain of over 0.25 inches that is
much needed and should help with fire weather concerns.

High temperatures over the weekend will be little cooler with highs
in the mid to upper 80s due to the cloud cover and rain.

As an upper level ridge builds over the western US, the northern
stream will take a dip to the southeast and allow a secondary
frontal system to move across on late Monday into Tuesday that is
expected to bring drier conditions along with overnight lows in the
lower to mid 60s and closer to the seasonal norm.

07/Rua

&&

.AVIATION...
(00Z TAFS)
Issued at 631 PM CDT Thu Oct 1 2026

Convection will continue to decrease through sunset, however
nocturnal storms will move onshore toward early Friday. Additional
diurnal convection is anticipated tomorrow. This may produce
periods of lower vis and ceilings. Winds will be mostly light and
vrb tonight, but SE at 5-10 kts tomorrow.

&&

.AVIATION...
(18Z TAFS)
Issued at 1235 PM CDT Thu Oct 1 2026

Showers remain possible for all sites through the afternoon and
early evening and begin dissipating after sunset. KBPT will keep
VCSH through the entire TAF period. Southerly winds around 10-15
knots with gusts to near 20kts with winds trending towards light
and variable as the sun sets.

Some showers/storms may bring gusts above 25kts. Also, storms
potentially dropping visibility for a brief period of time to
MVFR/IFR. Away from the convection, VFR conditions will prevail
through the TAF period. Will watch the convection closely and
amendments will be issued if needed.

KAEX may experience a brief drop in visibility in the early
morning hours just before sunrise due to some patchy fog.

/86/

&&

.MARINE...
Issued at 226 PM CDT Thu Oct 1 2026

The gradient between low pressure over the Plains and high pressure
over the southeast US will bring moderate east to southeast winds
and moderate seas into the start of the weekend. Over the weekend,
widespread rain and storms will impact coastal waters, reducing
visibility and causing locally higher winds and waves as a frontal
boundary nears the coast. This front will move out into the coastal
waters early next week with a period of moderate to strong offshore
flow.

&&

.FIRE WEATHER...
Issued at 226 PM CDT Thu Oct 1 2026

A very moist and tropical like air mass is expected to move into the
region through the weekend. This will increase rain chances and
humidity levels. Minimum afternoon relative humidity values are
expected to be over 50 percent on Friday and over 60 percent for the
weekend. Also, the probability for a widespread wetting rain is over
80 percent through the weekend. This should help reduce fire danger
as we move into early October.

&&

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

$$

PUBLIC/FIRE/MARINE...07
AVIATION...05