Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

171
FXUS63 KLSX 011125
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
625 AM CDT Sat Aug 1 2026

.KEY MESSAGES...

- Cloudy and cool conditions are expected today with occasional
  showers.

- After several days of seasonably cool temperatures, a gradual
  warm up is expected by the middle to later part of the week.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 118 AM CDT Sat Aug 1 2026

Vertically stacked low pressure centered near Keokuk, Iowa this
morning will slowly track east southeast across Illinois today.
Winds have already shifted to the west across the region, but
expect another shift to the north with cooler air pouring in
today. Although the humid, unstable warm sector has long sense
departed our region, low and mid level moisture wrapping around
the low will bring plenty of clouds and showers to the region
today, preventing much if any warming. Showers will be most
widespread across the northern half of the area closer to the
track of the low, with the axis gradually shifting southeast as
the low moves today. With little vertical depth to work with,
these showers will be fairly light in nature. The low exits to
the east on Sunday and the showers do, too. With more sun we
will finally be able to warm up a bit, but only to about 80
degrees. That`s still nearly 10 degrees below normal and quite
unusual for this time of year.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 118 AM CDT Sat Aug 1 2026

As the trough moves east, ridging extending northeast from the
western US ridge will nudge into the area in its wake. At the
surface, high pressure pushes through the Great Lakes Monday and
into the Ohio Valley on Tuesday. This puts our area on the
western edge of a cool, continental air mass with winds turning
from northerly to easterly and eventually southerly by midweek.
Daily sunshine will help to modify the air mass with high
temperatures climbing through the 80s to near 90 by Wednesday or
Thursday. Moisture from the Gulf remains blocked by the advance
of high pressure, so we`ll be working with recycled moisture
locally with dewpoints likely in the 60s through Wednesday, a
modest level of humidity for this time of year.

A trough arriving in the Pacific Northwest this weekend pushes
back against the Western US ridge and emerges out into the
Plains by midweek. A shortwave rounding the base of this trough
brings our next rain chances as it interacts with the first bit
of return Gulf moisture Wednesday night into Thursday. Another
wave quick on its heals produces another round of showers and
storms Thursday night into Friday. Where each of these rounds
forms and tracks will be determined later, but for now at least
two rounds are likely across the region, focused mainly at
night. With greater moisture returning to the area, the
potential for an east-west boundary and some training along it,
we will have to monitor this time period for the potential for
locally heavy rainfall and flash flooding.

Uncertainty on temperatures increases during this time period
as how warm we get will depend on where a frontal boundary sets
up and how much cloud cover is around. Guidance which keeps the
front further north brings hot temperatures back into the 90s as
early as Wednesday. While the probability of 90 degree heat
increases each day through next weekend, there`s still a lot of
uncertainty with passing waves each day having some effect on
the front`s position. NBM interquartile spread for high
temperatures is 7 to 10 degrees from Thursday onward, relatively
high spread for this time of year. On the warm side of things,
temperatures could rise into the mid 90s with humidity returning
to push heat index values back over 100. But if the front stays
closer to the area then clouds and showers are more likely to
hold temperatures back several degrees, potentially remaining in
the 80s.

&&

.AVIATION /12Z TAFS THROUGH 18Z SUNDAY/...
Issued at 620 AM CDT Sat Aug 1 2026

A day more reminiscent of early October is expected with low
clouds, on/off light rain showers, and even some drizzle/fog.
IFR ceilings are forecast across the area most of today and
tonight, with conditions first improving in central Missouri
terminals close to midnight followed by KUIN closer to daybreak
Sunday. For metro St. Louis, the improvement likely will wait
until later Sunday morning. As for visibilities, mostly VFR
conditions are expected, though look for low MVFR in any fog
and/or shower activity. Winds will turn out of the northwest,
with some gusts in the 20-25+ knot range. Wind speeds/gusts are
expected so slowly subside tonight.

&&

.CLIMATE...
Issued at 221 PM CDT Fri Jul 31 2026

Unseasonably cool temperatures are expected today. High
temperatures will be near the record coolest high temperature
for August 1st. Below are the record min max values for each
climate site:

SiteRecord (Year)Forecast

St. Louis   73 (1985)76
Columbia 71 (1985)73
Quincy73 (1973)74


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

&&

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

&&

$$

SHORT TERM...Kimble
LONG TERM...Kimble
AVIATION...Gosselin
CLIMATE...Kimble