Area Forecast Discussion

947
FXUS63 KLSX 221744
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
1144 AM CST Sat Nov 22 2025

.KEY MESSAGES...

- Dry weather with seasonably mild temperatures is expected this
  weekend.

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

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 1139 AM CST Sat Nov 22 2025

(Through Late Tonight)
Issued at 249 AM CST Sat Nov 22 2025

Low clouds along with some fog and patchy drizzle will gradually
push off to the southeast by midday. Sunshine should become more
prevalent with time today. Temperatures are expected to top out in
the 50s by afternoon, or slightly above normal for the date.

A weak cool front is expected to move through the mid-Mississippi
Valley overnight. There may be some increase in high-level
cloudiness associated with this front, but otherwise, no impacts to
sensible weather conditions are forecast. Lows tonight will remain a
bit on the mild side (upper 30s to low 40s) as surface winds veer to
the southwest ahead of the front.


Gosselin

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 1139 AM CST Sat Nov 22 2025

(Sunday through Friday)
Issued at 249 AM CST Sat Nov 22 2025

(Sunday - Sunday Night)

The front that moves through tonight is a Pacific front, so the air
mass coming in will not usher in any cold air. In fact, high
temperatures on Sunday should be warmer than today due to plenty of
sunshine expected. Highs are forecast to range from the upper 50s to
mid 60s from north to south.

Increasing mid/high level clouds ahead of the next weather system
should lead to another mild night Sunday night. Lows are only
forecast to drop back into the upper 30s (south-central Illinois) to
mid 40s (central Missouri).


(Monday - Monday Night)

A midlevel shortwave trough is forecast to move out of the south-
central Plains into the Upper Midwest by Monday night, with a weak
surface low tracking across the Missouri-Iowa border. Widespread
rain showers are expected Monday afternoon/evening ahead of the
midlevel trough in the presence of increasing low-level moisture
convergence. This round of rain still looks to be of much shorter
duration than the event that just ended last night. This should
really limit total rainfall amounts. Probabilities on the LREF for
at least 0.25" of rain are near 50%, but drop below 20% for at least
0.50" of rain. Any widespread rain though on the heels of
yesterday`s rain however would be very beneficial and could put
another dent to the ongoing drought.


(Tuesday - Friday)

Ensemble guidance remains in pretty good agreement that a secondary
mid/upper level trough will move across the Upper Midwest late
Tuesday/Tuesday night. This will help bring in a colder air mass
into the mid-Mississippi Valley as we head toward the Thanksgiving
holiday. Clusters of the 500-hPa height pattern still show more
spread later next week with the strength/speed of the mid/upper
level trough as it heads eastward. This means there is still
uncertainty with temperatures and how cold it will be in/around the
Thanksgiving holiday. Trends over the past 24 hours have been toward
a weaker/faster trough evolution, which would mean only slightly
below normal temperatures for the holiday. The deterministic NBM is
near the 75th percentile, with highs in the mid to upper 40s
Wednesday through Friday. Those temperatures would be about 5
degrees below normal on average for late November. Lows are also
expected to drop back below the freezing mark both Thursday and
Friday mornings for the first time in about 2 weeks. The good news
for holiday travelers is that it looks dry through at least
Thanksgiving Day itself. The LREF has 6-hr probabilities for
measurable precipitation below 10% through Thursday.


Gosselin

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1139 AM CST Sat Nov 22 2025

Challenging TAF forecast on track for this afternoon and again
overnight. Confidence is high in a period of VFR for the metro
St. Louis TAFs, as pesky stratus has finally moved to the south
and mixed out. Have stuck with IFR stratus longer at
UIN/COU/JEF, but think with time all sites will see at least
some VFR into late this evening.

Confidence then deteriorates tonight with potential reformation
of fog/stratus. Have gone the most pessimistic at UIN/COU/JEF,
where limited mixing today will mean it won`t take much to get
renewed fog/stratus. However, IFR restrictions are certainly
possible in metro St. Louis as well and this will be re-
evaluated for the 00Z issuance. With an incoming weak front,
leaned more towards IFR stratus formation. Winds will be fairly
light and variable through the period.


&&

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

&&

$$

WFO LSX

NWS LSX Office Area Forecast Discussion