720
FXUS63 KLSX 112327
AFDLSX

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

.KEY MESSAGES...

- Confidence in widespread rainfall has increased incrementally
  across the area, particularly across the southern half of
  Missouri and southern third of Illinois (50-80%), but there
  remains a wide range of potential amounts.

- High confidence exists that a significant warming trend will
  materialize from Sunday through the middle of next week.


&&

.SHORT TERM...  (Through Late Thursday Night)
Issued at 1239 PM CST Wed Feb 11 2026

Benign weather conditions remain the status quo in the short term
period, as surface high pressure will linger throughout the day
today before sliding just to the east of our area tomorrow. While we
will continue to see a steady stream of high level cirrus clouds
today, this is about the extent of weather excitement that will be
observed in our area, as surface winds will remain very light, and
temperatures are likely to climb to slightly above average by late
afternoon (upper 40s to low 50s).

Overnight tonight, surface winds are expected to remain nearly calm,
but the persistence of high level clouds may restrict the efficiency
of radiative cooling slightly. While we will still likely see
morning low temperatures near the freezing mark, this will likely be
several degrees warmer than it otherwise would be without those
clouds present.

During the day tomorrow, the aforementioned surface high pressure
will move eastward slightly, which will cause winds to turn to the
southeast and increase slightly. While this may provide a very
modest temperature boost from warm air advection, this particular
fetch is not particularly conducive to this, and this effect is
likely to be counteracted by the continued increase of mid and high
level cloud cover. As such, temperatures tomorrow will likely end up
reaching similar values as today when all is said and done. Models
have also consistently hinted that a subtle mid/upper level impulse
may also provide just enough mid-level moistening and lift to
produce some very light showers, but dry low levels will likely
prevent this from amounting to much more than some sprinkles or very
light accumulating rain (less than 1/10 inch). Best chances for the
latter will likely be across our far southwestern counties in
central MO and the Ozarks, but still very low (20% or less).

BRC

&&

.LONG TERM...  (Friday through Next Wednesday)
Issued at 1239 PM CST Wed Feb 11 2026

Once again, the primary concern with the short term period continues
to be the potential for meaningful rainfall across a large portion
of the region over the weekend, followed by a period of well above
average warmth. While the latter comes with a relatively high degree
of confidence, there remains considerable uncertainty in this
weekend`s rain potential, particularly in regards to coverage and
amounts.

Before we get to all of that, Friday is likely to be another
relatively benign weather day as a broad upper ridge across the
central CONUS inches farther eastward. While additional subtle mid-
upper level impulses will round the top of the ridge and move
through the Central Plains and lower Mississippi River valley, an
ambient dry airmass will very likely (90+%) keep our area dry
Friday. Meanwhile, modest surface flow will turn to the due south,
driving a modest increase in warm air advection and another
incremental boost in temperatures. As such, we can expect
afternoon high temperatures to reach well above average, and
likely into the mid 50s to low 60s with a high degree of
confidence. The only potential stumbling block with this
temperature forecast is cloud cover, as increasing mid/high clouds
may slow this warming slightly if it arrives sooner than
currently projected.

Otherwise, attention turns fully to the approach of a shortwave
trough and surface low from the west, which is expected to move
across the Southern Plains and lower Mississippi River valley
between Saturday and Sunday. While it is very likely that the track
of the surface low center will end up just south of our area, even
under the most northerly ensemble solutions, warm air advection
overrunning a stalled surface boundary remains likely (50-80%) to
produce at least some precipitation across the southern half of
Missouri and southern third Illinois. As has been the case in past
forecasts though, there remains considerable variability
potential amounts and northward extent of this precipitation
owing to high ensemble spread in the track/strength of the
approaching shortwave and low.

While it has been noted in recent forecasts that the "operational"
deterministic model solutions for both the GFS and ECMWF have
recently displayed more northerly and wet solutions, these trends
have not yet been quite as convincing in the broader ensemble
envelope, which limits our confidence that this trend is
meaningful. Instead, while there has been a slight shift toward
higher precipitation amounts overall, cluster analysis continues
to indicate a wide range of viable solutions. These range from a
widespread, soaking rainfall between 0.5 to 1.5 inches (and
locally 2+") on the upper end in all areas south of I-70, to
meager amounts barely reaching even 0.5 inches in the drier
solutions. The former, wetter solutions tend to feature a deeper
and slower closed low, while the latter tends to be associated
with a weaker and faster open wave. In any case, we continue
refrain from jumping on any particular solution over the other
just yet, as there is still too much variation to make such a
claim at this time range. It should also be noted that there may
be a sharper gradient on the northern flank of this precipitation
than is currently being resolved in ensemble guidance, and even
the wetter, more northerly solutions may not yield much meaningful
precipitation at all in northeast Missouri and west-central
Illinois.

In spite of these differences though, confidence has increased
slightly that at least SOME rain will fall across our southern half,
with much lower confidence that the amounts will be significant and
enough to meaningfully improve ongoing drought conditions.

Beyond Sunday, an upper ridge will quickly build behind the
departing trough, along with increasing southerly and eventually
southwesterly flow. This will almost certainly drive a rapid warming
trend from early to mid week, supported by significant positive
temperature anomalies. By Tuesday, 850 mb ensemble mean temperatures
(LREF) reach the 95th to 98th percentile of climatology, and this
continues into Wednesday as well. While are many things that may
impact how well this will translate to surface temperatures at this
time range, confidence is nonetheless quite high (90+%) that we will
see several days of well above average temperatures Sunday onward.

BRC

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 524 PM CST Wed Feb 11 2026

Dry and VFR conditions are expected through the period. Light and
variable winds will turn out of the southeast (140-160 degrees) at
less than 10 knots late on Thursday morning.

Britt

&&

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

$$

WFO LSX