286
FXUS63 KLSX 230258
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
858 PM CST Sat Nov 22 2025

.KEY MESSAGES...

- Another storm system will bring light rain to the area Monday
  afternoon Monday night ahead of a cold front. Behind the front,
  slightly colder than normal temperatures and dry weather is
  expected through the Thanksgiving holiday.

- Even colder air is possible beyond the official forecast late
  next weekend. The pattern suggests at least some threat of
  wintry precipitation late next weekend into the first week of
  December, but it`s too early to ascertain any additional detail
  at this time.


&&

.SHORT TERM...  (Through Late Sunday Night)
Issued at 121 PM CST Sat Nov 22 2025

Stratus has finally had more of a southwestward push this
afternoon, allowing for sunshine to warm temperatures into the 50s
this afternoon in most areas, with 40s hanging on where stratus
has been persistent (western IL and central/southeast MO).

A weak cold front will move through the region tonight into early
Sunday morning. The latest guidance, particularly the RAP, shows
fairly high low level moisture in the 925mb layer and below.
Therefore, this lingering moisture and subtle low-level lift
should allow for additional stratus/fog development tonight into
early Sunday morning, especially in areas that did not mix
efficiently this afternoon. Have upped cloud cover and low
temperatures to account for this.

Drier air should filter into the low-levels on Sunday, allowing
for skies to go partly cloudy. Therefore, temperatures into the
mid 50s/low 60s seem reasonable.

Deitsch

&&

.LONG TERM...  (Monday through Next Saturday)
Issued at 121 PM CST Sat Nov 22 2025

A shortwave will push toward the region on Monday. The latest
deterministic/ensemble guidance suggests the mid/upper forcing
will be enough for widespread rain Monday afternoon into Monday
night, departing through Tuesday morning. Fortunately, any
appreciable instability looks to stay well south of the CWA, thus
no severe weather, or even thunder, is expected with this system.

High pressure spills into the region Tuesday through Thursday
which should bring a period of tranquil weather, albeit a little
cooler than normal (temperatures in the 40s).

Precipitation chances will ramp up once again next weekend,
particularly Saturday and beyond as a trough digs into the western
CONUS, putting the Midwest in southwest flow aloft. While rain
looks the most likely through the official forecast period,
ensemble guidance is suggesting at least some threat of wintry
precipitation late next weekend into early next week as an early
Arctic airmass spills into the Plains and Upper Midwest beneath
the more active southwest flow aloft. Details are obviously low at
this point and guidance is not going to give the resolution
needed to resolve individual waves in this pattern this far out in
time, but there is at least a threat from Sunday and beyond. This
is something we will continue to monitor through the upcoming
week!

Deitsch

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 850 PM CST Sat Nov 22 2025

The low stratus that had been impacting KCOU and KJEF through much
of the prior day has begun to advect northeastward and is heading
toward KUIN - timed to impact that terminal around the start of
the forecast period with IFR flight conditions. Its current
trajectory has it just skirting KSUS and KSTL, with a low chance
for low MVFR/high IFR ceilings at these two terminals around the
start of the period. As for fog, the signal has become clearer,
with confidence increasing in impacts at most of the local
terminals, the exception being KSTL. There is still a low chance
for fog here, but confidence in impacts is too low to include in
the TAFs at this time. For KCOU and KJEF, visibilities may drop
lower than currently forecast, with both terminals being on the
eastern edge of where the signal for denser fog is. If fog ends up
being more dense at these two terminals, it may take longer to
dissipate in the morning than indicated. Once fog and associated
low stratus dissipate during the mid morning, VFR flight
conditions are expected through the remainder of the day.

Elmore

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX