436
FXUS63 KLSX 082337
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
537 PM CST Sun Feb 8 2026

.KEY MESSAGES...

- Warm and largely-dry conditions are now forecast through mid-
  week. The highest chances (25-40%) for light rain will be late
  Tuesday into early Wednesday across the Ozarks and southwest
  Missouri.

- Precipitation chances increase Thursday into the weekend, as
  high as 50%, but there is still plenty of dry time in between
  these chances.


&&

.SHORT TERM...  (Through Late Monday Night)
Issued at 238 PM CST Sun Feb 8 2026

A very weak shortwave is evident on mid-level GOES Water Vapor
imagery, which is forcing a transient surface low currently tracking
through southern Iowa and northern Missouri. Ahead of the wave, a
plume of cirrostratus kept temperatures subdued along and south of
the Missouri River this morning, but the skies are clearing and
temperatures will continue to rise above normal over the next few
hours. This clipper is also helping to draw moisture into the
region, with surface dewpoints across western Missouri 15-20 degrees
warmer than across eastern Missouri and western Illinois. As the sun
sets and winds slacken amidst weak high surface pressure, some high-
resolution guidance is hinting at patchy fog developing in eastern
Missouri along the Mississippi River. This area is where moisture
advection and somewhat stunted diurnal heating would overlap to
maximize this potential. That said, latest runs of the NBM and HREF
are backing off on the intensity compared to earlier iterations.
While I won`t be surprised to see a few areas of patchy fog in low-
lying parts of eastern Missouri and western Illinois, impacts look
very unlikely (less than 10%).

Nearly all available guidance paints a stronger warm advection
regime across the Mid-Mississippi Valley on Monday, with anomalously
high mid-level heights and southwesterly flow throughout the
boundary layer promoting dry, warm conditions to start the work
week. As has been the case the last few days, there will likely be a
strong (up to 20 degrees) west-east gradient to temperatures given
the stronger ridging and warmer 850mb temperatures over western
Missouri. Regardless, Monday looks like the pick of the week between
near to above normal warmth and dry conditions. Winds pick up out of
the southwest Monday evening in advance of a stronger cold front
that will traverse the forecast area on Tuesday.

MRB

&&

.LONG TERM...  (Tuesday through Next Sunday)
Issued at 238 PM CST Sun Feb 8 2026

The speed of Tuesday`s cold front is coming into greater clarity,
with a preponderance of guidance featuring a more rapid passage
through the region Tuesday morning. While the current forecast
represents continued timing uncertainty and features near-70-degree
temperatures in the Ozarks, we may very well see a cooler, cloudy
day areawide Tuesday. The quicker frontal passage also dashes any
precipitation chances save for the Ozarks and southwest Illinois,
and even those areas remain dry in the eyes of some models with
current chances capped at 30-35%. With the quicker, more progressive
frontal passage, any wavering of the front between late Tuesday and
early Thursday will not impact the CWA and we will very likely (90%)
remain dry.

The Mid-Mississippi Valley remains under the influence of cooler
northerly winds at the base of a surface ridge over the Great Lakes
through at least early Thursday, by which point the quasizonal flow
aloft becomes a bit more amplified out of the southwest. Nearly all
deterministic guidance and a few ensemble members do show one last
weak clipper approach the region Thursday into early Friday before
that amplification occurs, though they vary drastically on local
impact (from widespread light rain to no precipitation at all).
Currently there are some broad-brushed 30-40% PoPs across the
entire region, which I imagine will be refined spatially as the
clipper comes into focus.

A more potent trough is still modeled to eject from the Desert
Southwest at some point late-week and track east through the
southern CONUS. A stronger surface low is forecast to develop as a
result, though where and when this intensification occurs is not
clear. EOF patterns of the global-scale ensembles continue to
suggest the timing of the wave is still the greatest certainty sink.
Solutions continue to vary by as much as 24 hours and several
hundred miles as to the track of the system, though it still appears
that even the worst-case scenario for our region would feature
nothing more than widespread rain late Friday or Saturday. The
threat for light snow or a rain/snow mix remains quite low (10% or
less) on the northern edge of the system, mainly owing to a lack of
sufficiently-cold air in most solutions. It does also seem like any
scenarios tracking the low very far north, which would open us up to
more widespread rain and perhaps a few thunderstorms, are no longer
in the ensemble envelope. Continuing to look ahead beyond Saturday -
a return to warmer, slightly more active weather remains favored in
CIPS Extended Analog guidance and CPC outlooks.

MRB

&&

.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 526 PM CST Sun Feb 8 2026

Dry/VFR conditions with light southeasterly winds veering more to
the south are expected through the period. There remains a low
chance of fog impacting the area, but crossover temps are pretty
low with low temperatures tonight forecast above those values.
Therefore, not expecting too much in the way of fog so no mention
in any of the terminals.

Gosselin

&&

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

$$

WFO LSX