Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

125
FXUS63 KLSX 062343
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
643 PM CDT Mon Apr 6 2026

.KEY MESSAGES...

- A narrow band of snowfall is expected tonight across
  northeastern Missouri and west-central Illinois, with
  accumulations confined mainly to elevated and grassy surfaces.
  The chance for travel impacts remains very low.

- Warmer temperatures starting around the end of the workweek
  will coincide with an unsettled weather pattern that will bring
  multiple rounds of rain to the area this weekend into next week.


&&

.SHORT TERM...  (Through Late Tuesday Night)
Issued at 219 PM CDT Mon Apr 6 2026

Broad troughing is present over the eastern half of the CONUS this
afternoon per water vapor imagery. Low to mid-level confluence along
the western periphery of this feature will increase tonight,
strengthening frontogenesis over the Middle and Lower Missouri
Valley. Within this region, light precipitation will blossom this
evening, initially being high-based and struggling to reach the
surface. However, with increasing low-level saturation,
precipitation will reach to the surface, starting initially as rain.
Where precipitation rates are greatest, wetbulbing and dynamic
cooling will push low-level temperatures to near freezing, allowing
for a changeover to snow or at least a rain-snow mix. Confidence is
greatest in this occurring within a narrow corridor across
northeastern Missouri and west-central Illinois, where model
soundings show lift focused within or just beneath the dendritic
growth zone.

A significant limiting factor to impactful snowfall is marginal
surface temperatures. Even within the corridor of greatest rates,
surface temperatures will struggle to drop below 32 degrees. This
will be exacerbated by ground temperatures above freezing. Road
sensors as of this writing are reading in the mid to upper 80s
across this portion of the area, with values this past morning
bottoming out around 40 degrees. While temperatures Tuesday morning
are forecast to be colder, confidence is low that they will be cold
enough to allow for snowfall to readily accumulate on paved
surfaces. This will limit accumulations to mainly elevated and
grassy surfaces. Isolated trouble spots on pavement can`t be ruled
out where snowfall rates are greatest, allowing for brief
accumulation on roadways.

Precipitation coverage and intensity wanes after sunrise Tuesday
morning as frontogenesis rapidly weakens, pairing with warming
temperatures to eradicate any impacts and melt snowfall.
Temperatures outside of central and southeastern Missouri are
expected to be cooler than today, with many locations struggling to
warm out of the 50s thanks to cloud cover and cooler 850mb
temperatures. Low to mid-level ridging will amplify across the
Middle Mississippi Valley starting Tuesday evening, leading to
warmer air advecting into the region. As a result, Tuesday night`s
lows will be warmer than tonight`s, with most locations remaining
well above freezing.

Elmore

&&

.LONG TERM...  (Wednesday through Next Monday)
Issued at 219 PM CDT Mon Apr 6 2026

At the start of the extended forecast period, guidance consensus is
that upper-level flow across the Middle Mississippi Valley will be
subtly southwesterly as a shortwave moves through the Northern
Plains; its surface reflection traversing the US-Canadian border.
Between this feature and surface high pressure drifting eastward
from the CWA, low to mid-level flow will become increasingly south-
southwesterly through the day, advecting warmer air into the region
and pushing temperatures back to above seasonal normals. A cold
front associated with the aforementioned surface low will stall just
north of the CWA per deterministic guidance thanks to the lack of
robust northwesterly flow, with dry and warm conditions expected to
continue through much of Thursday.

A relatively weaker shortwave quickly passing through the Midwest
Thursday night into Friday paired with flow becoming increasingly
zonal across the Middle Mississippi Valley will allow for the front
to sink further southward closer to or into the CWA on Friday,
leading to increasing chances for showers and thunderstorms.
Confidence is low to medium in this convective activity, as it will
be forced via subtle and difficult to resolve disturbances within
the flow aloft amidst rising heights. Thermal and wind profiles are
unfavorable for strong to severe thunderstorms then, reflected by
little to no signal for such hazards among AI/ML severe-based
probabilities.

Confidence in the front`s position decreases Saturday and beyond,
with guidance showing solutions spanning from it remaining
positioned across the CWA to it retreating northward as a warm front
as upper-level ridging amplifies across the Midwest. This will be
occurring ahead of a deepening trough over the western CONUS that
will send several disturbances through the central portion of the
country from late weekend through next week. As a result, our
weather will remain unsettled through next week with multiple
chances for rainfall regardless of the exact placement of the
front.

Elmore

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 627 PM CDT Mon Apr 6 2026

VFR flight conditions are expected to prevail across the area at
least through 05-07Z. A band of precipitation will develop across
northeast Missouri into west central Illinois during that 05-07Z
time frame which will bring MVFR ceilings/visibilities to those
locations. The precipitation is expected to start as rain, but
then change to snow before sunrise, and end by mid to late Tuesday
morning. MVFR ceilings may spread as far south as central and east
central Missouri as well as southwest Illinois between 10-14Z
Tuesday morning, however confidence is low in these lower
conditions stretching that far south. Could also see some IFR
ceilings in northeast Missouri and west central Illinois between
12-18Z but confidences is also low in these IFR conditions.
Ceilings will lift slowly after the precipitation ends from late
Tuesday morning and through the afternoon.

Carney

&&

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

$$

WFO LSX