Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

249
FXUS63 KLSX 142315
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
515 PM CST Sat Nov 14 2026

.KEY MESSAGES...

- Cool weather continues this weekend, with a gradual
  moderating trend next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 128 PM CST Sat Nov 14 2026

Broad troughing aloft is leftover in the wake of the midweek storm
system. While the core of the trough continues through New England
today, expansive surface high pressure behind it continues to spread
across the central US, with its axis near the Mississippi
River. This has led to clear and cool conditions. Despite
plenty of sun, temperatures have only reached into the mid to
upper 40s today at the time of writing. With the surface high
keeping winds calm tonight, we`ll see another good radiational
cooling night, with the cold spots dropping into the low 20s.
There is, however, a little bit of cloud cover stemming from a
trough traversing the Four Corners and heading into Texas. This
little bit of high level cloudiness could keep our southwestern
portions from dropping as cold as last night. But if conditions
remain clear all night, we`ll be just as cold as this morning.

While the surface high reaches the Mississippi River this evening,
it will remain dominant over our region for several more days as it
slowly moves east toward the Ohio Valley. The result for us will be
a gradual air mass moderation in place with daily sunshine helping
to take the bite out of this Arctic air mass. However, clear and
calm nights will lead to continued freezes even as daytime highs
nudge back into the upper 50s to 60 degrees by Tuesday.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 128 PM CST Sat Nov 14 2026

Quiet and dry weather continues at least through midweek as the
upper level ridge builds over the Mississippi Valley and the
surface high drifts across the Ohio Valley and into the Mid Atlantic
Region.  Highs warm up to near seasonal normals in the mid 50s by
Monday, and then further into the upper 50s Tuesday, and then 60s on
Wednesday and Thursday as southerly flow increases ahead of the next
upstream short wave. Global guidance shows little moisture return
through at least Tuesday with ridging over the eastern 1/2 of the
CONUS blocking the Gulf, so the sky should remain clear to mostly
clear through that period. The clear sky and continuing light winds
overnight will allow temperatures to fall into the 20s again Monday
and Tuesday mornings in most locations.  However, increasing
southerly flow on the western side of the surface ridge will keep
temperatures from falling as much on Wednesday morning except in
sheltered locations.  Then there should be some moisture return into
the region Wednesday and Wednesday night as a short wave crosses the
Rockies and forces cyclogenesis over the Plains. Deterministic
guidance is in pretty good agreement up to that point in the
forecast, but begins diverging Thursday into Friday.  There`s
disagreement between the GFS and ECMWF on the amplitude and
orientation of the short wave as it moves from the Plains into the
Midwest Wednesday night into Thursday.  This leads to differences in
the strength of the surface low, how far southeast the associated
cold front travels, and how much moisture is pulled up into the Mid
Mississippi Valley ahead of it.  The GFS is largely dry for Thursday
and Friday, but the ECMWF is showing stronger moisture return and
prints out around 1/2 an inch of QPF. About 20-30 percent of the
LREF members have precip for our area which agrees well with the
latest NBM forecast.  Therefore chance PoPs for the end of the
forecast period continue to look reasonable, along with temperatures
warming well above normal in southwest flow ahead of the front.

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 509 PM CST Sat Nov 14 2026

With light winds, cold air temperatures, and relatively warm
water temperatures, there is a medium chance for river fog late
tonight into early tomorrow morning. This limits impacts to
KJEF, KSUS, and KCPS. There is a very low chance that fog
becomes dense enough to freeze; however, its shallow nature and
warm ground temperatures are expected to mitigate this threat.
Otherwise, VFR flight conditions are expected through much of
the period.

&&

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

&&

$$

SHORT TERM...Kimble
LONG TERM...Kimble
AVIATION...Elmore