878
FXUS64 KLCH 211724
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1124 AM CST Fri Feb 21 2025

...New AVIATION...

.KEY MESSAGES...

- An arctic type chill will be felt this morning before the air
  mass begins to modify later today and tonight with no further
  cold weather advisories expected at this time.

- An upper level disturbance and a surface low will combine to
  produce widespread shower activity with a few thunderstorms that
  will bring a cold soaking rain from late Saturday afternoon
  into Sunday.

- A warm up is expected early next week as decent sunshine and a
  south wind return.

&&

.SHORT TERM...
(Today through Sunday night)
Issued at 325 AM CST Fri Feb 21 2025

An arctic air mass is lingering into this morning as strong high
pressure over the Central Plains continues to work to the south.
Wind chills across a majority of the forecast area are in the
teens, although mid and high level clouds are invading the
forecast area so this may help keep air temperatures from falling
too much further. Still with wind chills in the teens the cold
weather advisory will remain in effect until 9 am this morning.

The arctic origin high pressure system will work south but become
weaker and more stretched during the day that will decrease cold
air advection into the forecast area that will allow air mass to
begin to modify. However, with southern stream becoming more
active, cloud cover will increase helping to filter out solar
heating and keep things on the chilly side right into the weekend.

An upper level disturbance dropping south from the Rockies will
get caught up in the southern stream and move eastward across the
region during the weekend. Moisture and isentropic lift will
increase ahead of the disturbance that skies will remain cloudy on
Saturday with some light rain increasing during the afternoon
hours.

During Saturday night, the approach of the upper level disturbance
will induce a surface low to form along a coastal trough over the
western Gulf. The low will move in tandem with the disturbance to
the east with the center staying over the northern Gulf waters.

Modest southerly flow aloft will increase moisture values during
Saturday night into Sunday with PWAT values increasing to between
1.10 inches and 1.35 inches, which is roughly between the 75th and
90th percentile of daily norms, and mean layer relative humidity
values over 80 percent. The increasing southerly flow will over-
ride the cooler surface conditions, helping to increase isentropic
lift and thus widespread shower activity.

A cold soaking rain is expected from Saturday night into Sunday
with rainfall amount averaging between 1/2 and 1 inch north of the
HWY 190 corridor, with between 1 and 1 1/2 inch south of the HWY
190 corridor down to the coast. Some elevated CAPE and weak
instability is noticed, along with good mid level shear values and
mid level lapse rates, so some embedded thunderstorms may form
withing the rain shield.

However, with warm sector staying offshore, storms are not
expected to become surface based, this will lower any severe
threat, although some small hail can not be ruled out with any
storm that develops due to the mid level shear, lapse rates, and
low wet bulb temperature height. The overall lack of convection
should also keep rainfall rates low that will also decrease any
flood risk with rainfall amounts occurring over a long duration
and not in a short period.

Rain will end from west to east on Sunday afternoon as the surface
low moves off to the east.

Rua

&&

.LONG TERM...
(Monday through Friday)
Issued at 330 AM CST Fri Feb 21 2025

A warm up in temperatures in expected early to middle part of next
week as southerly winds return and decent solar heating is noted
on each day.

A weak cold front is expected to move across the forecast area on
Wednesday night. However, moisture return looks shallow ahead of
this system, along with upper level dynamics staying to the north,
therefore, frontal passage at this time looks to be dry with only
an isolated shower at best expected.

Air mass behind this cold front will be of a modified
Pacific/Canadian variety that will bring temperatures back to near
seasonal norms.

Rua

&&

.AVIATION...
(18Z TAFS)
Issued at 1119 AM CST Fri Feb 21 2025

VFR conditions will continue through most of the TAF period with
overcast but high ceilings. Ceilings will slowly lower dropping
to 5k feet and become overcast by the afternoon. Near the end of
the TAF period rain will enter the region from the west with -RA
expected at BPT and LCH starting around 15Z.

Winds remain from the north but will decrease from 10 knots down
to 5 knots.

&&

.MARINE...
Issued at 305 AM CST Fri Feb 21 2025

The cold surface high pressure system over the Central Plains will
weaken and move further south. This will help weaken the pressure
gradient and the cold air advection that will then decrease the
offshore flow during the day. Therefore, the small craft advisory
will end around noon today.

Over the weekend, a coastal trough will form helping to keep a
modest northeast flow in place for Saturday. A surface low is
expected to form along the trough by Saturday night into Sunday.
The low will track across the coastal waters. A modest east to
northeast flow will persist, however, if the low strengthens more
than anticipated, winds will be stronger with higher gusts and a
small craft advisory may be needed. The low, combined with an
upper level disturbance will bring widespread shower activity with
a few thunderstorms from Saturday afternoon into Sunday.

The low will move off to the east by Monday with high pressure
ridging across early next week to bring modest southerly flow to
the coastal waters.

Rua

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  44  31  51  36 /   0   0  10  30
LCH  43  36  49  42 /   0   0  20  70
LFT  48  36  54  42 /   0   0  10  50
BPT  43  36  50  43 /   0   0  30  80

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until noon CST today for GMZ450-452-455-470-
     472-475.

&&

$$

SHORT TERM...07
LONG TERM....07
AVIATION...14