Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

981
FXUS63 KLSX 150838
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
238 AM CST Sun Feb 15 2026

.KEY MESSAGES...

- Unseasonably warm temperatures are forecast Monday through
  Thursday, potentially threatening daily records on Wednesday.


&&

.SHORT TERM...  (Through Late Tonight)
Issued at 237 AM CST Sun Feb 15 2026

Light rain may linger first thing this morning in parts of
southeast Missouri and southwest Illinois, but should move out by
mid morning as the low-level cyclone shifts eastward into the
southeastern CONUS. Some patchy drizzle cannot be ruled out behind
the accumulating rain due to low-level saturation and weak near-
surface convergence. Some patchy fog has also developed in
northeast Missouri and west-central Illinois where mid/high level
cloudiness has moved off to the southeast. The low stratus will
advect out of the region from northwest to southeast, with parts
of southeast Missouri and southwest Illinois not seeing the sun
until closer to about 2000 UTC. This means that we will have a
rather unusual southeast (cooler) to northwest (warmer)
temperature gradient for this afternoon`s highs. Readings should
top out in the low 60s across parts of northeast Missouri, with
highs only in the low 50s for parts of southeast Missouri and
southwest Illinois.

At least areas of fog should develop overnight tonight across
southeast Missouri and southwest Illinois. This is where the low
stratus will depart latest today, so more limited mixing is expected
in those locations. In addition, this area saw quite a bit of
rainfall over the past 24 hours (0.75-1.50" for most) so near-
surface moisture is quite high. Finally, favorable conditions for
radiational cooling are forecast overnight with a mostly clear sky
and light winds near a surface ridge of high pressure. Short-term
model guidance is a bit variable with how widespread (and dense) the
fog will be, but there is a possibility of seeing at least some
patchy dense fog in our southeastern counties. HREF probabilities
for visibilities at or below 1/4SM are in the 50-60+% range. For
now, did add patchy dense fog mention but we will have to monitor
the possibility for more widespread dense fog, which would
necessitate a dense fog advisory. Outside of the fog chances, a
quiet seasonably mild night is on tap with lows ranging from the mid
30s to low 40s. Similar to today`s expected highs, warmest readings
should be in northeast Missouri with cooler temperatures further to
the southeast.


Gosselin

&&

.LONG TERM...  (Monday through Saturday)
Issued at 237 AM CST Sun Feb 15 2026

(Monday - Thursday Night)

A warming trend begins on Monday as winds turn out of the southwest
at lower levels of the troposphere. Strong low-level warm air
advection combined with partial sunshine is expected to combine to
yield high temperatures in the 60s areawide. These readings would be
nearly 20 degrees above normal for the date.

There remains strong confidence in well-above normal temperatures
continuing through the day on Thursday. There remains some
uncertainty as to which of Wednesday or Thursday will be the warmer
of the two, but regardless, highs in the mid 60s to low 70s appear
likely. Probabilities for highs of 70+ from the NBM are now similar
each of these afternoons, with the highest chances (60-90%)
along/south of I-70. Similar to yesterday, both the 75th and the
90th percentiles though are about 1-2 degrees higher across most of
the area on Thursday, so there may be a bit more potential on
Thursday compared to Wednesday. Regardless, it will be very warm for
the middle of February as even the 25th percentile of the NBM each
day is 20-25+ degrees above normal. Wednesday still has the best
chance of potentially seeing records, mainly due to the fact that
Wednesday`s record highs are several degrees cooler compared to
Thursday. Please see the CLIMATE section below for more details.

Much of the upcoming week looks dry, with little/no signal for any
widespread rainfall. A pseudo-dryline moves through the region late
Tuesday night, bringing a low chance (20-30%) of showers. Model
guidance also is hinting at some elevated instability, so also could
not rule out a thundershower.  A cold front is forecast to move
through the bi-state area late Thursday/Thursday night. Moisture
return ahead of this boundary looks weak/suspect, as surface
dewpoints look to struggle to get back close to the 50 degree mark
east of the Mississippi River. The stronger mid/upper level forcing
for ascent also stays over the Upper Midwest. This means that there
is the potential for this front to move through mostly dry. LREF
probabilities over the 24-hour period ending at 1200 UTC Friday top
out at 40-60% along/east of the Mississippi River. Ensemble guidance
also suggests some potential for weak (>250 J/kg) surface-based
instability as the GEFS+GEPS has probabilities Thursday
afternoon/evening in the 10-20% range in south central and southwest
Illinois.


(Friday - Saturday)

Much cooler temperatures are forecast to end the week into next
weekend. However, the incoming air mass looks like one that will get
us closer to normal levels and not any real cold air with bite.
Mostly dry weather is also favored, though we will have to watch a
trailing midlevel shortwave trough moving across the region late
Friday/Friday night. This feature may help yield some light
precipitation during this time period (most likely a cold rain). The
best signal for any measurable precipitation at this time appears to
be across southeast Missouri and southwest Illinois where LREF
probabilities are in the 20-30% range ending Saturday morning.


Gosselin

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1027 PM CST Sat Feb 14 2026

Rain continues to move west to east through the forecast area. IFR
visibilities and ceilings are persisting, and they will continue
until late morning/early afternoon when rain and low-level clouds
scatter. Patchy fog is possible in the morning as clouds exit from
northwest to southeast. After clouds scatter, VFR conditions will
prevail through the remainder of the TAF period.

Jaja

&&

.CLIMATE...
Issued at 232 AM CST Sat Feb 14 2026

Daily record high temperatures may be threatened early/mid next
week. Here are records between Tuesday 2/17 and Thursday 2/19 at our
three official climate stations:

        Tuesday 2/17        Wednesday 2/18      Thursday 2/19
KSTL    77/1911             74/1971             77/2016
KCOU    74/2011             71/2017             77/2017
KUIN    72/2017             68/2017             72/2017


&&

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

$$

WFO LSX