239
FXUS64 KLCH 202322
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
522 PM CST Mon Jan 20 2025

...New AVIATION...

.SYNOPSIS...
Issued at 418 PM CST Mon Jan 20 2025

***RARE AND SIGNIFICANT WINTER STORM TONIGHT INTO TUESDAY***
***DANGEROUS COLD TEMPERATURES AND WIND CHILLS THROUGH THE WEEK***

Potent winter storm system taking shape near the S TX coast where
a forming surface trough is progged to strengthen over the coming
hours. Moisture continues to increase and deepen in the 850-700 MB
layer amid increasing lift, yielding a midlevel cloud deck that
has been steadily spreading northward over the area. Aloft, shortwave
energy over the SW states is beginning to drop into the base of a
longwave trough that encompasses the CONUS, and this energy will
provide the support needed for what looks to be a fairly robust
winter storm across the region tonight into Tuesday. Northeasterly
winds have been strengthening and becoming more gusty in response
to the developing surface trough. While temperatures have managed
to climb above freezing across the area, the increasing cloud
cover has limited "warming", and no sites have reached 40 degrees
as of this writing.

A summary of the latest headlines:

- Cold Weather Advisory from 6 PM this evening to 6 PM Tuesday for
  wind chills down to 12 to 16 degrees

- Extreme Cold Watch from Tuesday evening through Wednesday
  morning for wind chills between 5 and 15 degrees

- Winter Storm Warning with a light mix of precipitation
  transitioning to mainly snow overnight. Snow accumulations of up
  to 2 inches are expected from the Lakes region of southeast
  Texas into central Louisiana, with 4 and 8 inches across much of
  southwest and south central Louisiana and southeast Texas,
  especially along the I-10 corridor. Sporadic ice accumulations
  of up to 0.1 inch are also possible.

- Small Craft Advisory and Gale Warning in effect for the coastal
  waters zones for strong winds and hazardous seas.

24

&&

.SHORT TERM...
(Tonight through Wednesday night)
Issued at 418 PM CST Mon Jan 20 2025

What a time for a first shift back on the forecast desk after
being off of it for over a week. Quite a busy next 24 to 36 hours
as the low system over the western Gulf interacts with deepening
moisture and lift augmented by the approaching shortwave from the
west. While this would normally favor increasing rain and
possibly a few showers or storms over the area, an arctic airmass
entrenched across the area has created a much more complex
scenario. Air temperatures are expected to remain above freezing
through mid-evening, with onset of precipitation expected across
SE TX around the same time. Forecast soundings show a warm nose
evident around 700 MB, with profiles mostly below 0C. Any slight
adjustments to this warm nose and this would impact p-types at the
surface. At this point, a mix of types are expected with precip
onset this evening, with a brief window for flurries as well as
some freezing rain or ice pellets across SE TX. Precip will likely
transition to all snow overnight across the northern zones, while
a wintry mix develops across lower SE TX into SW LA after
midnight.

As the surface low progresses east across the Gulf of Mexico
overnight into Tuesday morning, colder air will begin to spread
south into the region, allowing all precip to transition to snow
over inland areas. There is the potential for some banding to set
up by Tuesday morning, especially along and south of the I-10
corridor, and this could lead to periods of heavy snow along with
localized higher accumulations. At this time, general
accumulations of up to 2 inches will be possible across interior
SE TX into central LA, while further south accumulation of 4 to as
much as 8 inches are expected.

Precipitation should quickly come to an end during Tuesday
afternoon from NW to SE across the area as the shortwave trough
pivots across the region. This will introduce a reinforcing arctic
high across the area which will bring extremely cold temperatures
and dangerous wind chills to the area. The Extreme Cold Watch will
likely be upgraded to a Warning within the next couple of shifts.
The cold temperatures will be exacerbated by clear skies and
lightening winds as the high center settles over the area, as well
as the lingering snowpack on the ground. Temperatures Tuesday
night are expected to falling into the teens across the entire
area, with apparent temperatures falling as low as the single
digits.

Unusually cold temperatures will linger through the day Wednesday
and into Wednesday night. Temperature distribution will be
dependent how much snow remains and where the deepest snow will be
located as the snow will reflect much of the energy away from the
surface, resulting in less heating.

24

&&

.LONG TERM...
(Thursday through next Sunday)
Issued at 418 PM CST Mon Jan 20 2025

Cold temperatures will prevail through the start of the long
term, especially as snow is expected to linger on the ground
through Friday. The last night of freezing temperatures for lows
is expected Saturday morning, with temperatures quickly moderating
through the weekend as the surface high moves east of the area. By
Sunday, high temperatures are expected to be back into the middle
to upper 60s with lows that morning in the middle 40s to lower
50s. Rain chances will increase again next weekend as the next
disturbance moves into the region.

24

&&

.AVIATION...
(00Z TAFS)
Issued at 522 PM CST Mon Jan 20 2025

Cloud deck is lingering around 7 to 8 kft at this hour with a
somewhat blustery northeast wind. Elevated northeast winds will
prevail on a tight gradient between high to the north and low
pressure moving over the Gulf. Ceilings will fall over the coming
hours as moisture and wintery precipitation move into the region.
Precipitation type will likely start as cold/freezing rain after
midnight before turning over to snow for much of the day.
Visibility will likely be impacted at times by snowfall, with
light to moderate intensities expected.

Low pressure skates swiftly to the east tomorrow with a sharp
cutoff of snow expected from west to east after 18Z. Ceilings will
improve with departing precipitation, however elevated north winds
will persist.

11/Calhoun

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  23  35  13  40 /  40  70   0   0
LCH  25  33  13  35 /  60  90   0   0
LFT  26  33  14  37 /  50 100   0   0
BPT  26  37  17  42 /  70  90   0   0

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Winter Storm Warning from midnight tonight to midnight CST
     Tuesday night for LAZ027>033-044-045-055-073-074-141>143-
     152>154-241>243-252>254.

     Extreme Cold Watch from Tuesday evening through Wednesday
     morning for LAZ027>033-044-045-055-073-074-141>143-152>154-
     241>243-252>254.

TX...Winter Storm Warning from midnight tonight to midnight CST
     Tuesday night for TXZ180-201-259>262-515-516-615-616.

     Extreme Cold Watch from Tuesday evening through Wednesday
     morning for TXZ180-201-259>262-515-516-615-616.

GM...Small Craft Advisory until 6 PM CST Tuesday for GMZ430-432-435-
     436.

     Small Craft Advisory until midnight CST tonight for GMZ450-452-
     455-470-472-475.

     Gale Warning from midnight tonight to midnight CST Tuesday night
     for GMZ450-452-455-470-472-475.

&&

$$

SHORT TERM...24
LONG TERM....24
AVIATION...11