Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

316
FXUS63 KLSX 270438
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1038 PM CST Thu Feb 26 2026

.KEY MESSAGES...

- Low relative humidity and gusty winds will lead to widespread Elevated
  Fire Danger on Friday. Where confidence is greatest in Red Flag
  Warning conditions occurring, a Fire Weather Watch has been
  issued.

- Confidence remains high (80%) in wintry precipitation impacting
  the region late Sunday into Monday morning, with the greatest
  travel impacts occurring north of I-70.

- An active pattern is expected next week, leading to multiple
  rounds of precipitation through the week.


&&

.SHORT TERM...  (Through Late Friday Night)
Issued at 253 PM CST Thu Feb 26 2026

Water vapor imagery this afternoon shows broad troughing present
across a majority of the CONUS; the trough`s axis positioned just
east of the CWA over the Ohio Valley. This has deep northwesterly
flow aloft over the Middle Mississippi Valley that has pushed a
surface ridge into the region, leading to mostly clear skies and
temperatures running above seasonal normals today. The surface ridge
will keep these calm conditions in place tonight, allowing for
radiational cooling to drop temperatures into the mid to low 30s.
However, these values are still above climatological normals.

Tomorrow, the surface ridge shifts eastward as a surface low moves
through far southern central Canada, causing the pressure gradient
to strengthen regionally. The placement of the surface ridge
supports southwesterly winds, and with the tightening pressure
gradient, strengthening winds through the morning and early
afternoon. Mostly clear skies promoting deep mixing, warming low-
level temperatures, and downsloping off the Ozarks will bump
temperatures for most locations into the low to mid 70s during the
afternoon. This warmth combined with low dew points will lead to RH
dropping below 30% for most locations, producing widespread Elevated
Fire Danger for a majority of the CWA thanks to the gusty winds.
Where confidence is at least 50% in RH dropping below 25% and
sustained winds reaching 15 kts (Red Flag Warning criteria) a Fire
Weather Watch has been issued for Friday afternoon. With winds and
dew points in this area forecast to reach just above criteria, the
decision on which zones to upgrade to a Red Flag Warning will occur
with the next forecast package when confidence increases further in
forecasted conditions.

Elmore

&&

.LONG TERM...  (Saturday through Next Thursday)
Issued at 253 PM CST Thu Feb 26 2026

Northwesterly flow will still be aloft over the Middle Mississippi
Valley on Saturday per guidance consensus. Within this flow, an
Arctic front will drop southward through the Midwest, passing
through the CWA early in the day. With flow through much of the
depth of the atmosphere being more west-northwesterly, the post-
frontal air will lag behind the FROPA, leading to many locations
seeing another day of well-above normal temperatures. There is a
signal for light precipitation along the mid-level front as it sinks
through the CWA during the afternoon, leading to low confidence (20%
chance) for rainfall.

The more notable chance for precipitation still looks to be Sunday
into Monday when a weak wave will pass through the Lower Midwest and
Mid South. While uncertainty still abounds concerning the details of
this system, guidance consensus has at least pushed back the onset
of precipitation to Sunday evening. As for the QPF spatial footprint
and magnitude, confidence is low. While the GFS/GEFS remains a
bullish outlier with storm total QPF, a majority of other guidance
has relatively lighter QPF. This is particularly the case with the
12z NAM, which has a stout low-level dry layer up through 00z Monday
that moisture will have to overcome to produce precipitation. The
NBM is beginning to ingest this drier NAM, combining with the less
aggressive guidance to tip the balance away from the GFS/GEFS and
lower forecasted snowfall amounts. Even with lower QPF, dynamics
Sunday night and early Monday morning will support precipitation
rates favorable for accumulating snowfall where surface temperatures
will be freezing or colder. Confidence is highest in this still
being north of I-70, though ground temperatures initially above
freezing will inhibit accumulation, especially on pavement. At this
lead time, wetbulbing and rates are expected to be great enough to
allow for accumulation on all surfaces within this portion of the
CWA. With the relatively lower QPF that a majority of guidance is
producing, a band of 2-4" of snowfall would result. If the more
robust GFS/GEFS QPF and lift within the dendritic growth zone is
realized, a band of 5"+ will be realized.

Along and south of the I-70 corridor, precipitation type is more
uncertain given marginal low-level temperatures. At the very least,
if snow and/or sleet mix in with the rain, warm ground temperatures
and at or just above freezing surface temperatures will limit
impacts. After sunrise Monday morning, precipitation will wind down
and shift east-southeastward as temperatures warm, quickly
decreasing the probability of impacts.

Given the plethora of impacts early in the period, little attention
was given to the details of the forecast beyond Monday. Ensemble
clusters and deterministic sources favor quasi-zonal to
southwesterly flow over the Middle Mississippi Valley, supporting
additional rounds of precipitation. With ensemble means showing
temperatures warming well above freezing, confidence is high that a
majority of this precipitation will be rain.

Elmore

&&

.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1036 PM CST Thu Feb 26 2026

Dry and VFR conditions are expected through the period. Light and
variable winds will shift out of the southwest on Friday morning
with gusts to around 20 knots at UIN/COU/JEF before decreasing
after 00Z.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Fire Weather Watch Friday afternoon for Audrain MO-Knox MO-Lewis
     MO-Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

IL...Fire Weather Watch Friday afternoon for Adams IL-Brown IL-Pike
     IL.

&&

$$

WFO LSX