126
FXUS63 KLSX 132350
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
550 PM CST Fri Feb 13 2026

.KEY MESSAGES...

-Rain will start up Saturday morning and last into the overnight to
early Sunday period for most.

-A warming trend will kick off Sunday and last through at least
 mid week with highs 15-20 degrees above normal.


&&

.SHORT TERM...  (Through Late Saturday Night)
Issued at 143 PM CST Fri Feb 13 2026

Weak high pressure will continue today and into this evening,
allowing high temperatures today to peak near 60 degrees. Our next
weather system is winding up on the lee side of the southern Rockies
today and will progress eastward in step with a mid level trough
just coming onshore over Baja. Rain will push into the forecast area
late tonight/early Saturday morning, enhanced by the associated
northward moving warm front.

Most of the region is expected to receive at least some rain, though
uncertainty is growing in how far north the beneficial rain will
push. Hi-res ensembles and individual members have trended slightly
southward with the latest runs, keeping portions of northeast
Missouri and west-central Illinois from receiving widespread
rainfall through the entire day. While guidance has been hinting for
days at a rather sharp QPF gradient on the northern side of this
system, confidence is growing that this may occur in our forecast
area. Far northern portions of the CWA are not expected to see more
than 0.25" of rain (30% chance of exceedance), while just south of
the HWY 36/I-72 corridor, rainfall amounts increase rapidly with a
70% chance of more than 0.25". The highest confidence in widespread
soaking rain is across southeast Missouri and southern Illinois
where there is a 60% chance of exceeding 1" of rain. Localized
amounts of up to 2" (via the 24 hr HREF LPMM) are possible where the
warm front stalls over the CWA and lift is locally enhanced, most
likely along and south of I-70. Despite the relatively high rainfall
amounts, this rain is expected to fall over 10+ hours onto dry soil,
keeping flooding concerns at a minimum.

Temperatures on Saturday will be stunted due to the cloud cover and
precipitation, resulting in highs peaking in the low 50s.


Delia

&&

.LONG TERM...  (Sunday through Next Friday)
Issued at 143 PM CST Fri Feb 13 2026

The system and associated rain will exit the region early Sunday. In
its wake a mid-level ridge will build in over most of the CONUS
while a surface high moves in at the surface. The mid-level ridge
will persist through much of the work week, resulting in a warming
trend is evident in the ensemble guidance. This includes the 850 mb
temperatures, which are forecast to exceed the 99th percentile
during this period. Temperatures will warm into the upper 50s to 60s
area wide Sunday through Tuesday. West to southwesterly flow and
deep mixing on Wednesday will help locally warm temperatures, adding
a few more degrees to an already unseasonably warm week. Portions
of southeast and east-central Missouri and far southwest Illinois
have a 30-40% chance of exceeding 70F Wednesday afternoon.
Elsewhere, highs have a 60-80% chance of exceeding 65F.

At the same time a surface low will slide through the central CONUS,
bringing a Pacific front through the mid-Mississippi Valley.
Moisture will be limited both ahead of and behind this feature,
resulting in a dry frontal passage. Another system will push through
the region Thursday into Friday, and guidance indicates this system
will be accompanied by a true cold front, starting a relative
cooling trend that will last through next weekend. There is an
increasing chance for precipitation with this system, though
uncertainty is high in the quality of moisture return and the
location of the system as it moves through, both of which will
impact precipitation chances.

Delia

&&

.AVIATION...  (For the 00z TAFs through 00z Saturday Evening)
Issued at 538 PM CST Fri Feb 13 2026

Dry and VFR conditions are expected through 12Z before rain
(80-100% chance) moves into JEF/COU by 14Z and the St. Louis area
terminals around 15Z. Ceilings and visibilities will initially be
VFR, but will slowly decrease to MVFR, and then IFR through the
late morning and afternoon. At UIN, the rain chances will be
lower, so have only included a PROB30 group between 17-23Z with
MVFR ceilings and visilities on Saturday. Winds will turn light
and variable tonight before turning out of the southeast (100-140
degrees) at 10 knots or less.

Britt

&&

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

$$

WFO LSX