851
FXUS63 KLSX 232243
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
543 PM CDT Fri Oct 23 2026

.KEY MESSAGES...

- High pressure remains in place allowing for our dry and warm
  weather continues well into next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 148 PM CDT Fri Oct 23 2026

An upper-level ridge will remain positioned over the Mid-Mississippi
River Valley through Sunday, stagnated by the configuration of the
wave pattern into an Omega Block. This pattern will result in very
little change in sensible weather from day to day with seasonably
warm temperatures and dry conditions. The only change through the
weekend will be the very slow departure of a surface high pressure
center and upper-level clouds of varying thickness streaming
overhead by Saturday through Sunday. The most pronounced nocturnal
radiational cooling during the period will be across southeastern
MO/southwestern IL and/or river valleys with low temperatures
in the 40s F and patchy morning fog, mainly low temperatures in
the 50s F elsewhere. High temperatures will continue to be in
the 70s F, near 80 F on Sunday depending on the thickness of
cloud cover.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 148 PM CDT Fri Oct 23 2026

Global model guidance is coming into better agreement on the
ejection of an upper-level trough into the Central/Northern Plains
and Upper Midwest Monday through Tuesday as the Omega Block breaks
down. With this track of the trough, it is increasingly likely that
the associated cold front does not reach the CWA, favoring similar,
seasonably warm temperatures continuing along with dry conditions.

It is not until late next week now, that there are any signs for our
sensible weather to change with varying signals for an upper-level
trough to propagate into the north-central CONUS. However, the track
and amplitude of the trough is uncertain which will influence its
ability to force an associated cold front east/southeastward. If the
front reaches the CWA, it would be accompanied by an opportunity for
rain and temperatures cooling closer to average late next week. If
the front fails to reach the CWA, there would be no clear catalyst
for seasonably warm temperatures and dry conditions to end. Ensemble
model guidance cluster analysis depicts these scenarios all being
valid possible outcomes at this point. Taking all scenarios into
consideration, probabilities of measurable rainfall range from 20 to
50 percent Thursday, onward, along with NBM interquartile ranges
increasing to between 10 and 20 F.

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 543 PM CDT Fri Oct 23 2026

Dry and mainly VFR conditions are expected through the period.
There will be some fog late tonight into early Friday in low
lying areas with MVFR and possible IFR visibilities including
at SUS and CPS. Otherwise winds are expected to remain light.

&&

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

&&

$$

SHORT TERM...Pfahler
LONG TERM...Pfahler
AVIATION...Britt