Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

891
FXUS63 KLSX 252359
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
659 PM CDT Mon May 25 2026

.KEY MESSAGES...

- Although there are daily shower and thunderstorm chances in
  portions of the area through the end of the week, the severe
  weather threat remains low.


&&

.SHORT TERM...  (Through Late Tuesday Night)
Issued at 200 PM CDT Mon May 25 2026

Broad surface high pressure extending form Buffalo, NY to St
Louis, MO has kept our comfortable, dry weather in place for one
more day. However, increasing high clouds observed today are a
sign of a coming change. There`s a slow moving cut off low over
Texas that`s causing a weak disturbance to gradually lift
northward through the lower Mississippi Valley. This is currently
producing widespread cloud cover and showers across the Deep South
with Gulf moisture slowly oozing northward as well. Current
dewpoints across our area are largely in the low 50s. However
just to the south some low 70s have crept into the Missouri
Bootheel. For tonight, the increased cloud cover will keep us a
bit warmer than we have been the last couple of nights, though
areas that remain more cloud free could once again drop into the
low to mid 50s.

On Tuesday, the slow moving cut off low continues to weaken and
expand northeastward with the low level moisture oozing back up
into our region. By the afternoon, those 70 dewpoints will be
nudging into our southern counties. As low level moisture
increases, we`ll also see instability increase with CAPE values
rising into the 500 to 1500 range, enough for showers and
thunderstorms to develop especially when aided by a weak surface
warm front and subtle energy aloft. The warm front (moisture
return) only makes it to about the Missouri River by Tuesday
afternoon, so areas north of there are likely to see another dry
day. Along and south of that front scattered showers and
thunderstorms are expected to develop. Wind flow aloft remains
quite weak, so we do not expect significant storm organization or
severe risk. The primary impacts will be localized downpours and
lightning. Precipitable water values rise up to about 1.8 inches
as the moisture nudges in, with a very moist sounding and skinny
CAPE indicating heavy rainfall rates. If any storms can linger in
one spot for more than an hour then a localized flash flood threat
could develop, but weak shear is expected to keep storms short
lived. Shower and thunderstorm activity decreases overnight
Tuesday night, but we can`t rule out some continuing into the
night with the subtle forcing from the decaying upper low.

Kimble

&&

.LONG TERM...  (Wednesday through Next Monday)
Issued at 200 PM CDT Mon May 25 2026

Changes are underway across the continent that will soon set up a
rather stagnant weather pattern. A deep trough is currently moving
onshore in the Pacific Northwest while another trough is spinning
near Hudson Bay, soon to be shoved southeastward. In between
these, ridging will quickly develop and extend far north into the
Canadian Arctic. This high amplitude ridge, with troughs on either
side, will establish a blocking pattern which lasts at least into
the first part of next week. Daily forecast high temperatures are
generally within 3 degrees of 80 every day, a sign of the
stability in the upper level flow pattern. These temperatures are
right around normal for this time of year. The rather stable high
temperature forecast doesn`t tell the full story, though, as that
will be seen more in the humidity (and rain chances). Our area
will be in the transition zone between dry continental air
spilling south around the ridge through the eastern US and very
humid air from the Gulf of America to the south. Where that humid
air exists there will be balmy nights and daily chances for
showers and thunderstorms. Where the dry air exists there will be
cooler nights with dry conditions. So for the last half of the
week into the weekend the primary focus will be on where that
moisture will be.

As mentioned in the Short Term section, the moisture first makes
its presence felt in our area on Tuesday, and it likely makes its
furthest push northward on Wednesday when our entire area sees
shower and thunderstorm chances and humid conditions. The first
significant digging of the eastern US trough Wednesday into
Thursday will push surface high pressure into the Great Lakes,
with a "back door" style cold front leading the initial push of
dry air to the south and west. Guidance still varies on how far
south and west to go with this front as it outruns the forcing
from its parent trough. Areas south and west have the better
chance of remaining in the humid air Thursday and Friday while
areas to the north and east are more likely to be in the dry air.
Rain chances follow this trend as well. A second, more potent
trough digging into New England Friday into Saturday will send a
reinforcing surge of drier air back to the south and west through
the center of the country behind it. This will shove the effective
back door front more thoroughly through our area, pushing the
humid air back south to the Gulf Coast and west to the High
Plains. Thus for our we can say that the humid conditions with
daily rain chances may come to an end as early as Thursday or as
late as Saturday depending on the location and progress of the
first front. Even if the first one is slow to move through, the
second one will finally get the job done. This sets up a very
comfortable weekend coming up with highs near 80, lows in the 50s,
low humidity, and dry weather.

Kimble

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 655 PM CDT Mon May 25 2026

VFR flight conditions are expected to prevail across the area
until 10-12Z Tuesday morning when showers and lower ceilings will
move across parts of the eastern Ozarks. Ceilings could fall below
1000 feet for a few hours during the morning in southeast
Missouri, but should rise back to VFR levels by early afternoon.
VFR ceilings between 5000-8000feet are expected across the
remainder of the area. Scattered showers and a few thunderstorms
will drift north through the day, affecting areas mostly south of
I-70. The heaviest showers could produce pockets of IFR visibility
in heavy rain.

Carney

&&

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

$$

WFO LSX