998
FXUS64 KLCH 011138
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
638 AM CDT Thu Oct 1 2026

...New AVIATION...

.KEY MESSAGES...

-Hot and humid conditions expected through the end of the week
 with temperatures above seasonal norms.

-An upper level ridge will break down by the end of the week allowing
 for increase in mainly afternoon showers and thunderstorms
 through Friday.

-An increase in the potential for heavy rainfall will come over
 the weekend as an upper level trough and surface frontal boundary
 will slowly move into the region and meet up with tropical
 moisture.

&&

.DISCUSSION...
(Today through Wednesday)
Issued at 1226 AM CDT Thu Oct 1 2026

The large scale upper level pattern over the southern CONUS is
dominated by a strong 500mb trough and closed low currently centered
over New Mexico. Deep tropical moisture associated with the remnants
of Hurricane Polo is associated with this feature. A weak high
pressure ridge remains over our area with the ridge axis extending
from the Texas Gulf Coast northwards into the mid-Mississippi
Valley. At the surface, a low pressure center was analyzed over
southwestern Kansas, with a cold front extending south through
Texas, while high pressure centered off the Carolina coast remains
in place over much of the southeastern US. The resulting southerly
flow is advecting Gulf moisture into the CWA, with surface dewpoints
generally in the 70-75F range.

The weak ridge overhead will break down moving into tomorrow as deep
layer moisture increases over the area, which will increase the
potential for isolated to scattered convection during the daytime
hours. Instability will be sufficient to support thunderstorms, but
does not look overly impressive for the Gulf Coast, with HREF mean
SBCAPE only around 1000 J/kg as well as a stable layer evident above
700 mb in CAM soundings. However, any thunderstorms that do
develop could bring some gusty winds given modeled DCAPE
approaching 1000 J/kg and lowest 300mb theta-e differences greater
than 30 K.

A period of active weather then looks likely from Friday through the
weekend and into early next week. By Friday, the upper-level low
will open up into a trough and lift off to the northeast, while
the associated surface low and cold front slowly translate
eastward across Texas and Louisiana. In addition to the Pacific
tropical moisture associated with these features, a second source
of moisture will arrive from the Gulf in the form of a tropical
wave rotating around an upper-level ridge centered over Florida.

The combination of East Pacific and Gulf tropical moisture streams
will result in extremely anomalous total column moisture over our
area through this time frame. LREF mean PWAT peaks in the 2.2-2.4
inch range on Saturday, which is near the daily maximum moving
average for early October. Even the LREF 10th percentile PWAT is
greater than 2.0 inches, which exceeds climatological 90th
percentile, lending further confidence to the degree of anomalous
moisture. Efficient warm rain processes will be favored with model
soundings depicting tall, skinny CAPE profiles and warm cloud
layer depths in the 12-15 kft range.

Bottom line here is that heavy rainfall will be the primary concern,
though details are low confidence at this lead time and will
likely be tied to the evolution of the frontal boundary. One
factor working against a widespread flooding event will be dry
antecedent conditions; much of the CWA is currently experiencing
Moderate or Severe drought, particularly our Louisiana parishes.
That said, the environment will certainly be favorable for very
heavy rainfall rates and the potential for isolated flash
flooding, with urban and poorly drained areas the most vulnerable.
WPC has most or all of our CWA under a Marginal (level 1/4) or
higher risk of excessive rainfall for each of Friday, Saturday,
and Sunday, with a Slight risk (2/4) outlooked on Saturday for our
LA parishes and coastal SE TX counties. Stay tuned to updates
over the next few forecast cycles as this time period begins to
come into high- resolution model guidance range. Temperatures
during this period will cool a bit owing to the increased cloud
cover and rainfall, with afternoon highs in the low to mid 80s
during the weekend while overnight lows hover around 70.

Another mid-latitude trough should push a secondary cold front
southward through the CWA around the Monday into Tuesday time
frame. This will advect drier continental air into the area,
ending the rainfall threat and allowing overnight lows to fall
into the low to mid 60s across the area.

64/Silas

&&

.AVIATION...
(12Z TAFS)
Issued at 634 AM CDT Thu Oct 1 2026

Light showers have been developing and moving inland along the
coast early this morning and coverage is expected to continue to
increase through the morning and early afternoon in response to
diurnal heating and increasing atmospheric moisture. Storms will
begin to wane by late afternoon and should be largely dissipated
by 23Z. Away from storms, southerly winds of 10-15 knots will
prevail through the day becoming light and variable after 00Z.

Jones

&&

.MARINE...
Issued at 1226 AM CDT Thu Oct 1 2026

Southeast winds up to 15-20 kt will diminish some during the day
Thursday, but will remain elevated around 10 kt through the rest of
the week and into the weekend. A storm system this weekend will
bring widespread showers and thunderstorms to the coastal waters,
with locally higher winds and seas near any storms.

&&

.FIRE WEATHER...
Issued at 1226 AM CDT Thu Oct 1 2026

Increasing moisture will lead to scattered showers and thunderstorms
developing over the area Thursday, with afternoon MinRH values
around 45 to 60 percent. A storm system is expected to bring
widespread wetting rains to the area for Friday through the
weekend, which should allow for an improvement in regional drought
conditions.

&&

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

$$

PUBLIC/FIRE/MARINE...64
AVIATION...66