262
FXUS63 KLSX 271038
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
538 AM CDT Tue Oct 27 2026

.KEY MESSAGES...

- Warm and dry conditions are expected to continue through the end
  of the work week.

- Chances for widespread rain showers return Saturday afternoon/night.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 306 AM CDT Tue Oct 27 2026

An upper-level ridge that has dominated our weather is beginning to
break down. This is allowing a shortwave to move into the Mid-
Mississippi Valley today, which will bring widespread mid/high
clouds into our area. The thicker cloud cover will help keep
temperatures a little cooler with highs in the low-70s this
afternoon. With the increased clouds associated with the shortwave,
no rainfall is expected due to a deep layer (~10 kft) of dry air
below the clouds. Any rain that would fall would most likely dry out
before reaching the ground creating some virga. If anything does
make it to the ground it will just result in some sprinkles, but the
chances of even sprinkles is slim. The cloud cover will move out of
the region tonight and into Wednesday. As a result, Wednesday`s high
temperatures will be a little warmer in the upper-70s and
low-80s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 306 AM CDT Tue Oct 27 2026

As the upper-level ridge continues to flatten through the week, the
surface high over our area will gradually move to the southeast.
This will allow for upper-level clouds to continue over the region,
but will also cause winds to shift more southwesterly. The
southwesterly winds will bring an increase of low-level warm air
advection to the area, bringing warmer temperatures for the end of
the work week with highs in the low-80s. Ensemble guidance is very
confident on this warm up with IQRs of less than 5 degrees.

Guidance shows signs of a pattern change coming this weekend. An
upper-level shortwave will move through the Mid-Mississippi Valley
that will bring cooler temperatures and a chance for widespread
rainfall. Both the LREF and NBM guidance shows a slight cool down
starting on Saturday and going into next week, with high
temperatures in the upper-60s and low-70s each day. Each day`s
entire IQR for the weekend and beyond are below the 25th percentiles
of Friday`s high temperatures giving more precedent of a cool down.
This system will bring a return of moisture into the area, which
should result in widespread rain showers Saturday afternoon/night.
Ensemble guidance shows a 70-90% chance of measurable rainfall
(greater than 0.01 inches) by Sunday morning, with a 40-50% chance
of seeing 0.25 inches or greater by the same time. Early next week
ensemble guidance shows there could be another shortwave move
through the area that could bring widespread beneficial
rainfall.

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 536 AM CDT Tue Oct 27 2026

VFR conditions are expected to prevail through the TAF period.
Thicker cloud cover will move into the region this afternoon for the
central MO and west-central IL terminals, but conditions will remain
VFR.

&&

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

&&

$$

SHORT TERM...Asel/Gosselin
LONG TERM...Asel/Gosselin
AVIATION...Asel/Kimble