707
FXUS63 KLSX 041104
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
504 AM CST Thu Dec 4 2025

.KEY MESSAGES...

- Cold temperatures are expected through tomorrow morning with
potentially record breaking lows in Quincy, IL.

- Dry weather is expected through Saturday before there is a chance
for a wintry mix (20-40% chance) Saturday night and Sunday.


&&

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 346 AM CST Thu Dec 4 2025

regional radars are showing some weak banding over the CWA early
this morning, but very little is reaching the ground.  MVN reported
a brief shower in the last hour, and the FAM RAP sounding supports
sprinkles or flurries the next few hours.  After that, dry weather
is expected through tonight as the southern stream shortwave is
staying south of the area tonight as a surface ridge moves south
into the Midwest.

Temperatures have already fallen into the teens and 20s across
the area early this morning behind a cold front that has now
moved into southern Illinois and southeast Missouri. Lows this
morning will still likely drop down into the single digits over
northeast Missouri and west central Illinois. We will still be
close to the daily record low of +2F set back in 2006 at Quincy.
Even though there will be some clearing today, highs will only
reach the teens and the 20s with the cold air advection and the
snow cover. By tonight, the ridge will move off to the southeast
allowing for some return flow over the western CWA which will
allow for quite a range in lows from west to east. Here again, we
will be close to the daily record low at Quincy on Thursday night
of +6F set back in 2005.

Britt

&&

.LONG TERM...  (Friday Night through Wednesday)
Issued at 346 AM CST Thu Dec 4 2025

The ensemble guidance is consistent over the weekend into early next
week that there will be a series of troughs moving through the area
in northwesterly flow aloft.  The first will be on Friday night when
a shortwave trough will move through the Upper Midwest which will
bring a weak front down into the area.   None of the LREF member are
producing precipitation over the area with this first system. The
NBM has pushed chances up to 20-40% on Saturday night with a more
pronounced trough late in the weekend, and expect these PoPS will
go higher as more of the LREF members are producing precipitation
Saturday night and Sunday. Precipitation types from both the LREF
and NBM are pointing toward a wintry mix of light snow and rain
with possible freezing rain on Saturday night and Sunday. QPF
amounts look to be light at this point (<0.05"), but this still
may change has as the surface low track comes into better
agreement in the models. Additional weaker troughs will move
through the area early next week, though <15% of the LREF members
are producing precipitation over the area at this time.

With the northwesterly flow aloft, below normal air is expected to
continue to linger over the region through at least Monday before
southwesterly low level flow sets up over the area by midweek. This
is supported by the NBM temperatures which has an IQR at STL which
is only 2-6 degrees for highs through Tuesday.

Britt

&&

.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 459 AM CST Thu Dec 4 2025

Dry and VFR conditions are expected through the period. North to
northwest winds will turn light and variable at UIN/COU/JEF by
mid/late morning and then later this afternoon at the St. Louis
area terminals.

Britt

&&

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

$$

WFO LSX