Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

827
FXUS63 KLSX 262304
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
604 PM CDT Mon Oct 26 2026

.KEY MESSAGES...

- Warm and mostly dry weather is forecast through the end of the week.

- There is a 30-50% chance of light rain this weekend. Widespread
  rainfall is not expected.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 257 PM CDT Mon Oct 26 2026

Our stubborn pattern of 70s for afternoon highs and mostly 50s for
morning lows will continue through Tuesday night as upper level
ridging and surface high pressure continue to dominate our sensible
weather. The ridge aloft is breaking down, and this will allow a
shortwave to ride its northern edge into the Mid-Mississippi Valley
tomorrow. The greatest impacts from this will include slightly
cooler temperatures than today due to increased cloud cover and a
slim chance of sprinkles late in the day and into the overnight
hours. Although the lift and saturation may briefly be in place for
sprinkles, dry low levels are expected to prevent any droplets from
reaching the ground.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 257 PM CDT Mon Oct 26 2026

The upper-level ridge will continue to flatten through the week, and
surface high pressure will be compressed to our south and east.
For the most part, the loss of the protective ridging will only
allow more high cloud cover to blow into the region. Despite
the clouds, low-level warm air advection is expected to pick up
in the middle of this week as winds veer to southwesterly. NBM
max temperature IQR spread yields high confidence in warmer
highs on Wednesday and Thursday, as it only reaches 2-3 degrees
centered around 78 degrees and 82 degrees respectively.

At the same time, a shortwave will be traversing the northern
Plains/upper Midwest, and its surface reflection will be pushing a
cold front into the Mid-Mississippi Valley. Deterministic guidance
disagrees whether or not the front will reach northern Missouri/west-
central Illinois on Thursday morning, or if it will have enough
moisture convergence along it to produce light rain. Our better
chance for rain will come Saturday night into Sunday morning as
another shortwave enters the region. This feature is forecast to be
weakening as it arrives, but to what extent is uncertain. Low-level
convergence does not look appreciable either, so a widespread
rainfall is not expected. NBM and LREF probabilities are still
consistent in showing a 30-50% chance of 0.25" of rain this weekend,
corroborating this.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 602 PM CDT Mon Oct 26 2026

Aside from the renewed threat for MVFR to IFR fog at times
tonight at KSUS and KJEF, dry and VFR conditions continue
through Wednesday. With fewer clouds overhead compared to last
night, and fog still developing despite those clouds,
radiational cooling will be efficient and promote the fog
development.

&&

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

&&

$$

SHORT TERM...Jaja
LONG TERM...Jaja
AVIATION...MRB