Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

766
FXUS63 KLSX 201058
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
458 AM CST Fri Feb 20 2026

.KEY MESSAGES...

- Winds will continue to gust up to 40mph across northeastern
  Missouri and west-central Illinois through late morning.

- Cooler temperatures return today through Monday before
  temperatures rebound during the middle of next week.

&&

.SHORT TERM...  (Through Late Saturday Afternoon)
Issued at 209 AM CST Fri Feb 20 2026

The strong synoptic low responsible for our severe weather and
fire weather threats yesterday is now occluded and pivoting
northeast though the Upper Mississippi Valley. An elongated
deformation zone on the trailing edge of the low extends from
northern Iowa through central Missouri. While nearly all of the
measurable precipitation is across Iowa, where the mid-level wave
is providing ample forcing, a few sprinkles/flurries are being
reported in western Missouri amidst low stratus associated with
the deformation zone. Temperatures are falling quickly behind the
main cold front, and will suppress temperatures significantly
compared to yesterday`s highs. While there will be some difference
with northward extent, high temperatures will be 20-30 degrees
cooler than Thursday`s. Sustained winds of 20-25mph gusting to
40mph are likely (70-80% chance) north of I-70 in Missouri and
Illinois today as the low departs, but will slacken through the
afternoon. While a few areas across the Ozarks extending to
roughly the Missouri River may dance with elevated fire danger for
an hour or two today, the spatial/temporal overlap of
sufficiently dry and windy conditions doesn`t really exist
compared to days prior.

In the wake of the strong mid-level wave, quasi-zonal flow aloft
will develop and allow for weaker embedded shortwaves to impact the
region tonight through Saturday morning. During this time, some high-
resolution guidance is hinting at patchy light precipitation
skirting areas along and south of I-70. This precipitation is along
a weak area of 850mb-700mb frontogenesis collocated with a
saturated layer. There is very little in the way of upper-level
support, so precipitation will remain light if it occurs at all.
This is supported by HREF and NBM probabilities of 0.10" of liquid
precipitation no higher than 10-15% across southeast Missouri
with near-zero chances further north. While some profiles do
suggest a few snowflakes, anything that falls will be unimpactful
after several very warm days raised ground temperatures.
Precipitation chances drop off through the morning, when dry
conditions and cooler temperatures stay in place through the
weekend.

MRB

&&

.LONG TERM...  (Saturday Night through Thursday)
Issued at 209 AM CST Fri Feb 20 2026

Very cool, dry northwesterly flow will keep our sensible weather
rather uneventful through Monday. NAEFS guidance suggests 850mb
temperatures near the 10th climatological percentile Sunday through
Monday, which lines up with our forecast lows Sunday night in the
teens and highs Monday struggling to warm out of the 30s that day
areawide. Most global-scale guidance agrees that a strong warm air
advection regime will arrive Tuesday, sending temperatures back into
the upper 40s to mid-50s. The prevailing southwesterly flow ahead of
a cold front to our north will more than likely lead to some
localized warming lee of the Ozarks due to downsloping. There is a
signal for an elevated fire danger (described more in the Fire
Weather Forecast) on Tuesday given this favorable warm/dry pattern
and global ensemble support for RH values below 35%, though the
exact timing of the warmup during the day will be crucial for this
threat to materialize.

Forecast uncertainty begins to increase from Wednesday onward as a
more zonal flow returns to much of the CONUS and a fairly
progressive upper-level wave approaches the Mid-Mississippi Valley.
The wave arrives sometime Thursday by most ensemble depictions,
bringing our next precipitation chances. According to most severe
weather guidance, that particular hazard is unlikely given the
forecasted pattern. Temperatures may take a temporary hit after
this system departs, but overall the pattern continues to favor
abnormal warmth through the end of the month.

MRB

&&

.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 450 AM CST Fri Feb 20 2026

Strong wind gusts up to 35kts continue to impact the regional
terminals, and MVFR stratus persists overhead at the central
Missouri terminals and KUIN. Latest satellite data shows this
cloud deck beginning to erode as the large-scale system begins to
depart, which will end the flight restrictions over the next few
hours. Winds will be slower to slacken, but they will weaken
through the morning into the afternoon. Dry VFR conditions prevail
after that amidst a light northwesterly wind.

MRB

&&

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

$$

WFO LSX