Area Forecast Discussion

350
FXUS63 KLSX 100818
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
218 AM CST Sat Jan 10 2026

.KEY MESSAGES...

- Another cold front moves in from the north this evening. A few
  brief snow showers are possible as the front moves through.

- After one cold day on Sunday, milder temperatures return early
  next week.


&&

.SHORT TERM...  (Through Late Sunday Afternoon)
Issued at 217 AM CST Sat Jan 10 2026

Light rain has spread across central and northern Missouri into
central Illinois this morning in an area of warm advection aloft in
the vicinity of an advancing cold front. Temperatures this morning
have been mild enough for all of this to fall as rain, however, as
the low levels cool behind the northwesterly wind shift, rain may
briefly change to snow across northeast Missouri toward the Quincy
area before ending this morning. Surface temperatures are expected
to remain near or above freezing, limiting any accumulation.
However, some frontogenetic banding may lead to a strip of more
intense forcing to cause an uptick in intensity just before it ends.
This may be enough to provide a coating on elevated surfaces.

The rest of the day will feature relatively mild temperatures for
January standards. The air behind this front is only briefly colder,
with winds shifting to the west and bringing mild air in again this
afternoon. We expect widespread highs in the 40s.

As a strong upper low winds up over the Great Lakes this evening,
another front pushes south behind it. This one has a more
substantial push of cold air with it which will send the temperature
tumbling this evening. Along moisture is somewhat lacking, there are
indications that there will be just enough instability along the
front for the potential for a thin convective line to develop. If
this precipitation falls as snow, we could see some brief snow
squall like conditions as the temperature quickly drops and winds
pick up in the deeper mixing behind the front. However, we have some
doubt as to 1) whether this convective line will form and 2) whether
the precipitation it produces will be rain or snow. Although it`s
quite mild ahead of the front, low level dry air may be enough to
allow wet bulb cooling for a switch to snow. Still, though, we`re
fairly confident that if this occurs impacts will be limited to
brief visibility reductions and gusty winds. Accumulation on roads
will be more difficult due to mild preconditions and limited
duration of this brief burst of precipitation. Even this potential
decreases as the front moves south this evening.

The temperature falls below freezing area wide tonight with gusty
northwest winds in the cold advection behind the front. This doesn`t
last long, though, as the surface high begins to move into the
region on Sunday. This transitions us to lighter westerly winds and
allows for a modest warm up into the 30s to near 40. That`s near or
slightly below normal for this time of year.

Kimble

&&

.LONG TERM...  (Sunday Night through Friday)
Issued at 217 AM CST Sat Jan 10 2026

While the upper trough pulls well to the northeast through New
England, surface high pressure pushes into the Deep South Monday
into Tuesday. Westerly flow around the top of this high brings more
mild air into our area, allowing for a warm up Monday into Tuesday.
The warmest day is likely to be Tuesday as low level flow turns
southwesterly in response to another potent low moving into the
Great Lakes. Behind this low another cold front pulls a piece of
Arctic air southward. The front moves through our region on
Wednesday. While up to about 50 percent of low resolution ensemble
members produce precipitation as the front/trough moves through our
area, the surface high to our south blocking Gulf moisture will
ensure that anything that falls will be light. It`s also likely to
be in the warm sector ahead of the front, so likely to fall as light
rain if it does so.

The initial trough moves quickly off to the east on Thursday, but
another trough drops south behind it for Friday into Saturday. So
our cool down behind Wednesday`s front will be relatively tame and
brief, but followed by another push of colder air this weekend.
Ensemble guidance varies considerably in the timing and intensity of
the colder push this weekend. Right now our confidence is fairly
high that we`ll be shifting back below normal at least briefly, but
just how cold is less certain. NBM probability of subfreezing high
temperatures reaches 50 to 70 percent across the entire forecast
area on Saturday.

Kimble

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1044 PM CST Fri Jan 9 2026

Scattered light rain is currently to the west of the TAF sites
along a cold front and will move east into the terminals
overnight, ushering in several hours of MVFR ceilings with it.
These MVFR ceilings have been slow to develop to our west, so I
have delayed their onset by a few hours. Where rain falls brief
MVFR visibility reductions are expected. The exception will be at
KUIN where snow is expected to mix in with the rain early Saturday
morning, resulting lower visibilities while snow is mixed in with
the precipitation.

This precipitation and the surface front will move out of the
terminals Saturday morning and ceilings are expected to improve
quickly to VFR in the wake of the precipitation. Winds will become
northwesterly and gusty behind the front Saturday morning, gusting
into the 20s. These winds will persist through the remainder of
the TAF period.

There is a 20% chance for another round of light precipitation
Saturday afternoon and evening moving north to south through the
terminals. Confidence in this precipitation occurring and
impacting specific terminals is low, so have left a mention out of
the TAF for now.

Delia

&&

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

$$

WFO LSX

NWS LSX Office Area Forecast Discussion