Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

759
FXUS63 KLSX 140843
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
243 AM CST Wed Jan 14 2026

.KEY MESSAGES...

- Temperatures today will fall into the 30s with gusty northwest
  winds, which will make it feel like its in the 10s/20s.

- Multiple cold fronts are expected to move through over the next
  several days. Below to well-below normal temperatures are
  expected, with the coldest stretch between Saturday and Tuesday.


&&

.SHORT TERM...  (Through Late Tonight)
Issued at 242 AM CST Wed Jan 14 2026

The synoptic cold front as of 0800 UTC is near the I-44/I-55
corridors in Missouri and Illinois respectively. This boundary
will move out of the area just before 1200 UTC. Strong low-level
cold air advection will commence in its wake, with temperatures
falling through the afternoon into the 30s. These readings would
be about 20- 30 degrees colder than 24 hours prior. In addition,
sustained wind speeds of 15-25 mph with gusts of 30-35+ mph are
expected. This will make it feel even colder, with wind chill
values in the teens and twenties. Some of the gusts in northeast
Missouri and west-central Illinois may approach 40 mph mid to late
morning, but should stay below advisory criteria (45+ mph).
Probabilities of max wind gusts from the NBM only peak out in the
20-25% range, but do climb to near 50% for 40+ mph gusts. This
field has shown quite a bit of skill with respect to peak wind
speeds behind cold fronts so far this winter season. Soundings
also do not show much in the way of 40+ knot winds at the top of
the mixed layer today, further buttressing the point that advisory
level gusts look quite unlikely.

Winds tonight will slacken off gradually as a surface ridge
approaches central/northeast Missouri by 1200 UTC Thursday. A clear
sky, weakening winds, low dewpoints (<20th percentile of
climatology) all point to a seasonably cold night. Lows in the teens
are expected areawide, with some low teens possible in
central/northeast Missouri where winds will be lightest. While these
lows will only be about 5-10 degrees below normal for the date, this
should be the coldest night so far of 2026.


Gosselin

&&

.LONG TERM...  (Thursday through Tuesday)
Issued at 242 AM CST Wed Jan 14 2026

(Thursday - Friday)

Seasonably cold and dry conditions will continue on Thursday as the
surface ridge of high pressure slides across the bi-state area and
into the Ohio Valley. Highs in the 30s are forecast, with the
coldest conditions east of the Mississippi River.

The focus for Thursday night remains on the potential for some light
snow, mainly along/east of the Mississippi River. Soundings continue
to show a lot of dry low/mid level air. This means a couple of
different things. For one, anything that does fall should be snow,
as wetbulbing would help cool any part of the lower troposphere
below the freezing mark. Secondly, the forcing needs to be strong
enough and last enough time to fully saturate the column to produce
any measurable precipitation at all. Deterministic guidance
continues to depict moderately strong low-level warm/moist advection
along/east of the Mississippi River, coincident with a cold frontal
passage and weak mid/upper level diffluence ahead of an approaching
trough. This should be deep enough forcing over a 3-6 hour period to
produce some light snow in these areas. LREF probabilities for
measurable snowfall are 50-70% along/east of the Mississippi River.
These probabilities are still a bit higher than the NBM (30-50%),
mainly due to some lingering differences in timing and uncertainty
with respect to the track of the mid/upper level trough axis. These
forecast PoPs are however trending closer to the LREF, which looks
to be the right direction. Future forecast PoPs are more than likely
than not to continue to climb over the next 24 hours, especially the
further east you go. Any snow that does occur looks light, with
probabilities for 1"+ of snow below 15%. Main limiting factors
include the antecedent dry air (which means it takes time to
saturate to produce any snow), the limited time duration of the
event (3-6 hours), marginal surface temperatures (near freezing),
and max lift centered below the dendritic growth zone (favors
columns being the dominant ice crystal habit).

Dry weather with moderating temperatures is expected on Friday ahead
of the first in a series of arctic cold fronts. Temperatures are
forecast to rebound back a bit above normal by the afternoon, with
highs in the low to mid 40s.


(Friday Night - Tuesday)

The first arctic cold front is expected to move through Friday
evening. There is still a signal for some light snow along/behind
this front, with multiple lobes of vorticity moving across the
region in broader cyclonic flow aloft. The setup looks conducive for
on/off snow showers/flurries through Saturday. The coverage of this
activity may not be too widespread, but I wouldn`t be too surprised
to see some streaks of light accumulating snow across the region.
The latest LREF shows 24-hour probabilities ending 0Z Sunday for
measurable snowfall are in the 50-80% range. Similar to Thursday
night PoPs, while very low to nonexistent right now, they are more
than likely to climb in future forecast packages.

A second arctic cold front is forecast to push through the region
sometime between Sunday afternoon and early Monday morning. This
timing discrepancy is why forecast uncertainty for Sunday`s high
temperatures in particular is still quite high. The inter-quartile
range of the NBM is on the order of ~15 degrees, though that has
decreased substantially compared to yesterday. Temperatures ahead of
the boundary should "warm" up (relatively speaking), so a faster
frontal passage could mean highs close to normal on Sunday whereas a
slower front would likely mean another day with highs mostly in the
20s (10-15+ degrees below normal). There is also some spread on how
cold the second arctic air mass will be. Conceptually speaking, with
mid/upper level ridging becoming more amplified across Alaska, it
would make sense that the proceeding air mass would be colder coming
down into the CONUS. The bottom line is that it looks cold through
at least Tuesday of next week, but exactly how cold is a question
mark. The current forecast temperatures Monday-Tuesday are closer to
the 75th percentile of the NBM, so forecast temperatures may get
colder with time.

In terms of low temperatures, it does look like either Sunday or
Tuesday morning will be the coldest. It does depend on several
factors though, most importantly probably is the timing of the
surface anticyclones themselves. One or both of these mornings may
have single digit lows. Those temperatures combined with even light
northwest winds could lead to below zero wind chill values. Chances
on the LREF for <0 (<-10) wind chills on Sunday morning are in the
30-70% (10-30%) range, but do drop by Tuesday morning as forecast
uncertainty increases.


Gosselin

&&

.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 942 PM CST Tue Jan 13 2026

A band of light to moderate rain will continue moving south over
the next 5 to 6 hours, and finally move out of our forecast area
into far southeast Missouri by 09-10Z. A cold front will move in
behind the rain overnight and turn the wind to the northwest.
Winds will increase to 15-20kts with gusts to 30kts behind the
front. The front is also expected to bring an area of MVFR clouds
between 2000-2500ft south into the forecast area early Wednesday
morning. Latest guidance suggests it will stay out of central
Missouri but much of eastern Missouri and all of Illinois will
likely see these low ceilings. Should see ceilings lift by early
afternoon, and scatter out by late afternoon/early evening. Gusty
northwest flow will continue until early Wednesday evening.

Carney

&&

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

$$

WFO LSX