034
FXUS63 KLSX 111014
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
414 AM CST Wed Feb 11 2026

.KEY MESSAGES...

- Rain approaches the region by late Saturday morning with
  widespread precipitation Saturday afternoon through early Sunday
  morning. Rain chances are highest south of I-70 (up to 60%).

- Temperatures gradually warm through the week with well above
  normal temperatures (widespread 60s) favored by the end of the
  period.


&&

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 313 AM CST Wed Feb 11 2026

The mean upper-level pattern features zonal flow, while at the
surface, high pressure is centered over the central Plains as low
pressure passes eastward over Arkansas. This surface low is tracking
along a cold front that moved through yesterday and currently
resides over southern Missouri and Illinois. Mid to high clouds
extend north of the boundary to I-70, but deeper moisture remains to
the south, keeping conditions dry through the pre-dawn hours.

Over the next 24 hours, surface high pressure will build into the
Mississippi Valley, leading to mostly clear skies. Despite the
sunshine, high temperatures will be limited by northerly surface
flow and continued cold air advection around the eastern side of the
surface ridge. NBM IQR values are tightly clustered in the upper
40s to low 50s for high temperatures today.

By late tonight, the ridge will build into the region ahead of
modest ridge amplification over the Plains, with light and variable
flow eventually backing out of the southeast on Thursday. The
southerly flow component, while mild, is not expected to cause a
significant warm-up, but rather maintain mild temperatures. This is
well represented in 850MB temperatures, with a nearly stationary 0C
isotherm hugging eastern Missouri through Thursday. Additionally,
700MB saturation will increase cloud cover over the region,
effectively limiting solar insolation, and keeping Thursdays
temperatures nearly identical to todays (magnitude and
distribution).

Maples

&&

.LONG TERM...  (Thursday Night through Tuesday)
Issued at 313 AM CST Wed Feb 11 2026

By Friday, a broad mid-level ridge will encompass the southeastern
U.S., drawing milder air northward through the Plains. This will
provide the eastward push necessary to clear sub-zero 850MB
temperatures from the region. Mid-level moisture and cloud cover
will increase late in the day, allowing temperatures to improve
upon Thursdays highs. With 3-5 degrees of mid-level warming
expected, highs should reach the 50s across most of the CWA, with
some low 60s near the Ozarks.

The primary chance for rain is centered on late Saturday into early
Sunday. Rain chances (40%) arrive in central and southeast
Missouri by mid-to-late morning, while the rest of the area should
remain dry until the afternoon. While overall trends have shifted
south, the latest GFS deterministic guidance has adjusted
slightly northward and further west. I am hesitant to rely on a
single run and continue to favor southward trends, as the best
mid/upper level lift is currently positioned over southern
Missouri and northern Arkansas. Significant rainfall is expected
to stay along and south of I-70, where ascent is maximized. Areas
in the far northern CWA may miss out on much of this
precipitation.

Latest LREF totals show a notable spread, with approximately 0.50
forecasted along I-70 and higher amounts toward southern Missouri
and Illinois. The 25th percentile suggests less than 0.05 near
I-70, while the 75th percentile sits around 0.40-0.50. Given these
spreads, further adjustments to the QPF are likely. Saturday
morning currently looks dry for most, with rain chances increasing
through the afternoon and exiting early Sunday morning.

NBM temperature spreads increase to roughly 10 degrees for the
remainder of the period. As the upper low departs, ridge
amplification will bring even milder air into the region.
Currently, the deterministic NBM undercuts the 25th percentile
(upper 60s); if this trend persists, we may see warmer
temperatures heading into next week.


Maples

&&

.AVIATION...  (For the 12z TAFs through 12z Thursday Morning)
Issued at 409 AM CST Wed Feb 11 2026

High pressure will build overhead through the day today. Winds
will be light and variable a large majority of the time with
mostly clear skies. VFR conditions persist through the period.

Maples

&&

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

$$

WFO LSX