835
FXUS63 KLSX 021110
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
610 AM CDT Fri Oct 2 2026

.KEY MESSAGES...

- Lingering showers in southeast MO / southwest IL this morning will
  diminish by this afternoon.

- Dry conditions and more seasonable temperatures are expected
  for the next week, with a slow warming trend Tuesday onward.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 317 AM CDT Fri Oct 2 2026

While widespread rain is gradually winding down early this morning,
seasonably rich moisture lingers across parts of southeast Missouri
and southwest Illinois ahead of a slowly advancing cold front. PWAT
values in this area remain above 1.5 inches (and even near 2.0
inches along our southeastern border), which far exceeds the 90th
percentile for this time of year. As the synoptic front moves south
through the morning, reinvigorated shower activity will be possible
in these areas as the boundary interacts with this lingering ribbon
of moisture. High-resolution model guidance continues to depict this
occurring, although there remains some disagreement regarding just
how south this new activity will form. In any case, rain may not be
completely done until after roughly noon today as drier air finally
shoves this moisture south of the area for good. Even if this does
occur in our area, the largely stratiform nature of this rain
(perhaps with some brief convective elements) should limit new rain
amounts to near 1/2 inch or less.

Otherwise, the most notable change for today`s weather will be a
significant drop in temperatures compared to yesterday, with
afternoon maximums expected to be a full 20 degrees cooler in most
areas (roughly 70 degrees), which is just a few degrees cooler than
the average high temperature for October 2nd. Overnight, the
combination of much lower dewpoints, clearing skies, and light
northeast winds should allow temperatures to drop into the low 50s
to mid 40s by tomorrow morning, with no additional precipitation
expected.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 317 AM CDT Fri Oct 2 2026

(Saturday - Sunday)

Rather pleasant conditions are expected over the weekend as a large
area of surface high pressure across the Great Lakes will maintain a
steady stream of dry easterly low level flow. The most notable
aspect of this weekend`s weather is expected to be a very slight
warming trend as the dry post-frontal airmass is slowly warmed by
persistent insolation. This should yield temperatures in the mid to
upper 70s by Sunday, which is slightly above the mathematical
average for this time of year but still very seasonable. Meanwhile,
dewpoints in the upper 40s to low 50s, light winds, and mostly clear
skies should continue to allow overnight temperatures to drop to
similar values each morning.

(Monday - Thursday)

Late Sunday through Monday, an upper level trough will dig into the
Great Lakes and briefly reinforce northwesterly flow aloft, and will
also send another weak cold front through the area. This is expected
to both act as a speed bump for our weekend warmup, and also further
entrench our area within a dry, continental airmass for the
foreseeable future. As such, temperatures Monday are likely to drop
back to within a few degrees above average, with hardly a cloud in
sight. In other words, excellent early fall conditions.

From Tuesday onward, long-range ensemble guidance continues to
suggest that a rather stagnant pattern will develop across the
CONUS, with a broad upper ridge across the western 2/3rds of the
country that slowly expands eastward. As such, temperatures are
favored to slowly warm over the middle and latter portion of the
week, with relatively minimal spread among ensemble members.
Meanwhile, the previously mentioned continental airmass is expected
to linger across the area for several days and significantly limit
precipitation chances for the next week, with almost unanimous
support for dry weather throughout the ensemble envelope.

&&

.AVIATION /12Z TAFS THROUGH 18Z SATURDAY/...
Issued at 604 AM CDT Fri Oct 2 2026

The primary concern during the 12Z TAF window is lingering low
cloud cover at the start of the period. A broad stratus shield
continues to reduce categories throughout the region, but
inconsistently from terminal to terminal. Ceilings are expected
to improve fastest at UIN, where VFR ceilings are expected to
develop within an hour of the start of the period. Ceilings are
then expected to improve further south later in the morning,
although the precise timing is uncertain. Some improvement has
already been observed at STL and SUS, but this may be temporary
as surrounding sites continue to observe MVFR (or lower)
categories, including upstream. However, by mid/late morning,
all sites are likely to return to VFR conditions.

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

&&

$$

SHORT TERM...BRC
LONG TERM...BRC
AVIATION...BRC