Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

996
FXUS63 KLSX 261106
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
506 AM CST Thu Feb 26 2026

.KEY MESSAGES...

- Warm, dry, and windy weather paired with dry vegetation will create
  widespread elevated fire danger conditions on Friday.

- Much colder weather will end the weekend. Wintry precipitation is
  very likely (80-90%) late Sunday into Monday, with the greatest
  potential for travel impacts north of I-70.


&&

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 326 AM CST Thu Feb 26 2026

Today will be benign with decreasing clouds and highs in the 50s to
low-60s increasing from northeast to southwest.

Widespread elevated fire danger is expected Friday afternoon. A
cloudless sky will allow for unimpeded mixing, allowing dewpoints to
fall opposite rapidly rising temperatures. Strong southwest winds
will be bringing in very warm air, some of it downsloping off the
Ozarks. The NBM max temperature forecast has risen slightly since
yesterday, but it`s likely not enough. It typically underperforms in
this type of regime given its natural proclivity to forecast cooler
temperatures within the cool season, and its failure to recognize
small scale orographic influences i.e. downsloping off the Ozarks.
The same can be said for the degree of mixing and thus the afternoon
dewpoints/relative humidity. For this reason, I raised the forecast
highs on Friday to the NBM 75th percentile and dropped dewpoints.
Elevated fire danger already seemed likely to occur on Friday, but
it now looks certain. Red Flag conditions are even possible (20-30%
chance) in central and northeast Missouri if conditions line up
correctly.

Jaja

&&

.LONG TERM...  (Friday Night through Wednesday)
Issued at 326 AM CST Thu Feb 26 2026

A potent cold front will pass through the CWA late Friday into
Saturday, but its exact timing and behavior are still uncertain as
well as the magnitude and speed of the cold airmass spilling into
the region. These uncertainties translate to a wide spread of 10-15
degrees in the NBM interquartile range in many locations for highs
Saturday afternoon. The strength of the cold front will also tighten
the temperature gradient more than models can resolve, adding
another layer of uncertainty. This doesn`t seem particularly
important, and for Saturday it`s not so much. The temperature
variability comes into play regarding the arrival of precipitation
late Sunday into Monday. The degree and timing of warming ahead of
the front and cooling behind it will dictate what impacts we see
from the early week system.

By Sunday morning, the aforementioned cold front will have cleared
the area and is forecast to be somewhere in the Mid-South.
Meanwhile, Gulf moisture will become unlocked and begin to overrun
the front, traveling into the cold airmass settled over the Mid-
Mississippi Valley. The addition of mid-level forcing via an
influx of vorticity lobes will provide perfect conditions for a
widespread precipitation event. Confidence is very high (80-90%)
that everywhere will see something hit the ground late Sunday into
Monday. Confidence remains very high (80-90%) that for locations
north of I-70, this will be snow. Current NBM probabilities put
accumulations here between 1-3", but this will likely change.
Things become more muddled with southern extent. The overrunning
warm, moist air will create a warm nose within the thermal
profile, but what impacts this has is uncertain. How deep will it
be? How high from the ground? How much warmer than 0C? How far
north will it exist? The answers to these questions tell us what
precipitation type(s) we can expect within the transition zone and
where the transition zone will be. As of right now we don`t have
those answers. Latest ensemble guidance has moved the corridor for
the greatest chance (<30%) for ice accumulations south into
southeast MO/southwest IL, but this may change in the next 4.5
days. The current transition zone now sits over the I-70 corridor,
but this may change as well. If ice does fall, travel impacts may
or may not occur due to the antecedent very warm temperatures on
Friday and Saturday. However, the strength of the cold airmass and
speed of the cold front may provide enough lead time for roads to
chill ahead of the precipitation and for ice to accumulate on
them. In short, there are many questions and not many solid
answers. What we`re confident in is this: water in some form will
fall from the sky late Sunday into Monday. North of I-70,
confidence is very high it will be snow. To the south, what form
the water will be in and how it reacts when it reaches the ground
is uncertain.

Global models show an active pattern continuing beyond Monday
alongside a slow warm-up through at least the end of the week. The
CPC Days 6-10 Forecast reflects this, with each map showing above
average temperatures and precipitation likely through next week.

Jaja

&&

.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 505 AM CST Thu Feb 26 2026

Dry and VFR conditions will prevail through the TAF period. Light
winds today will be highly variable in direction before settling
on southwesterly around 06z Friday and increasing in speed
through the morning.

Jaja

&&

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

$$

WFO LSX