408
FXUS63 KLSX 021718
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1118 AM CST Mon Feb 2 2026

.KEY MESSAGES...

- There is a 20-40% chance of a light wintry mix over southeast
  and east central Missouri into southwest and south central
  Illinois late tonight into Tuesday.

- Temperatures will not be as cold as last week with highs in the
  30 and 40s.


&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 316 AM CST Mon Feb 2 2026

The light snow that affect the northern and eastern parts of the CWA
last evening has moved into Indiana along with the upper trough that
generated it.  Temperatures early this morning are notably warmer
than the past few mornings even though they are in the 20s.   The
latest surface analysis is showing a warm front over western
Missouri with a cold front moving southward across the upper
Midwest.  The warm front will move through early in the day allowing
highs to climb higher than have in well over a week.  Then the cold
front and additional clouds will move into CWA setting up a contrast
in temperatures from north to south this afternoon with highs
ranging from the middle 30s over the northern and eastern parts of
the CWA to the upper 40s over parts of southeast Missouri.

The weather will remain dry through late tonight before the next
shortwave moves southeast into the Midwest in the northwest flow
aloft.   Low pressure will develop over southwest Missouri late
tonight and then move east into the lower Ohio Valley by Tuesday
morning. Models are showing some differences with how quickly the
precipitation develops over the CWA, with the NAM being more
aggressive developing light snow over the eastern CWA late tonight
and Tuesday morning whereas the other determistic models are mainly
dry over the area. Some of the CAMS are also showing signs of wintry
mix late tonight into tomorrow morning over southeast Missouri into
the eastern CWA which have slightly increased the HREF probabilities
for light snow and spotty light freezing rain in these areas.  At
this point, have increase PoPs late tonight to 20% over the eastern
CWA where there is an increased signal for frontogenesis, and kept
with the 20-40% NBM PoPs tomorrow morning, but added WPC QPF which
added  the potential for a dusting to 1/4" of snow over the eastern
CWA as well as trace icing for where there will be some spots of
light freezing rain on Tuesday morning over southeast Missouri and
southwest Illinois. Precipitation is expect to move out of southwest
Illinois on Tuesday afternoon.  Lows tonight will be in the 20s with
highs on Tuesday back in the 30s except in southeast Missouri where
they will be in the lower 40s.

Britt

&&

.LONG TERM...  (Tuesday Night through Sunday)
Issued at 316 AM CST Mon Feb 2 2026

Generally dry weather is expected from the middle of this week
through the weekend as the upper pattern goes through a slow
deamplification.  A large surface high will move through the Midwest
from Wednesday into Thursday followed by a cold front moving south
through the area late in the week followed by another large high
over the weekend. The upper trough associated with the front will
pass through the Great Lakes supplying little ascent, and there will
be little moisture associated with this front with less than 10% of
the LREF members producing any precipitation between Wednesday and
next Monday over the CWA. Temperatures will not be as cold as last
week and highs will continue to be mainly in the 30s and 40s with
lows in the teens and 20s.  The confidence in the temperature
forecast does lessen over the weekend as NBM 25th/75th percentile at
St. Louis widens from 7 degrees on Friday to 15 degrees on Saturday
and Sunday behind the cold front.

Britt

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1118 AM CST Mon Feb 2 2026

High-MVFR/low-VFR ceilings will continue to clear from west to east
this afternoon with VFR flight conditions prevailing areawide. Late
tonight/Tuesday morning a weak weather system will pass through the
region, with MVFR ceilings redeveloping. The greatest support for
precipitation with this system will be across southeastern MO and
southwestern IL points eastward Tuesday morning. However, there is
approximately a 30 percent chance of light freezing drizzle and/or
snow at St. Louis metro terminals along with IFR ceilings. Flight
conditions will improve again from north to south late morning
through afternoon as lower ceilings scatter. Winds will remain
light, becoming northeasterly late tonight and veering toward the
north through the day Tuesday.

Pfahler

&&

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

$$

WFO LSX