Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

915
FXUS63 KLSX 070354
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1054 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 06z TAFs through 06z Tuesday Night)
Issued at 1040 PM CDT Mon Apr 6 2026

A band of precipitation is spreading southeast from Iowa into
northeast Missouri and west central Illinois. While the lower
atmosphere is fairly dry at the moment, the precipitation will
increase moisture and bring lower ceilings to these areas by
08-10Z. Precipitation will start as rain, and then change to snow
before sunrise. IFR visibilities are expected with the snow, and
likely areas of IFR ceilings as well. VFR conditions are expected
to prevail farther to the south although there remains some
question on how far to the south the lower ceilings will push in
the morning...possibly as far as the Missouri River, although
the probability is low. Precipitation across northeast Missouri
and west central Illinois should taper off and end by 15-17Z.
Lower ceilings will lift slowly through late morning into the
afternoon, with low MVFR/IFR potentially lingering into early
evening across parts of northeast Missouri.

Carney

&&

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

$$

WFO LSX