Area Forecast Discussion

614
FXUS63 KLSX 161154
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
554 AM CST Fri Jan 16 2026

.KEY MESSAGES...

- Scattered snow showers will develop this afternoon and move
  southeast through the evening along and behind an Arctic cold
  front. Localized and brief bursts of moderate to heavy snow are
  possible with these showers which could significantly reduce
  the visibility and produce accumulations up to around 1/2 inch.

- Very cold weather is expected Saturday through Tuesday with the
  coldest temperatures Sunday, Monday, and Tuesday morning. Lows
  in the single digits to low teens are expected in most locations
  with sub-zero wind chill readings mainly north of I-70.


&&

.SHORT TERM...  (Through Late Tonight)
Issued at 315 AM CST Fri Jan 16 2026

The primary concern in the short range forecast is snow showers
developing this afternoon and continuing into the evening.  A cold
front will move through the area this morning which will shift the
wind to the west.  Low level cold advection behind this initial wind
shift is not particularly strong and short range guidance is in good
agreement showing westerly winds along with some limited insolation
pushing surface temps into 40s by early afternoon.  Forecast
soundings are showing deep mixing and steep low level lapse rates
this afternoon.  CAMs show scattered showers developing this
afternoon over northeast Missouri/west central Illinois due to the
low level instability and lift provided by a secondary front which
will bring much colder air to the region.  Precip should initially
start as rain, but will switch to snow between temperatures falling
due to evaporation and colder air moving in behind the front.  Low
level lapse rates remain steep behind the secondary front, and
soundings even show a bit of CAPE.  The resulting snow showers could
produce brief moderate to heavy snow resulting in minor
accumulations.  While widespread travel impacts are not expected,
the heavier snow showers will reduce the visibility significantly and
likely overwhelm the relatively warm ground temperatures resulting
in localized accumulations up to 1/2 inch causing slick spots on
roads.  Snow showers will end from northwest to southeast through
the late afternoon and evening but isolated light snow or
flurries may linger over the Ozarks beyond 06Z.

Carney

&&

.LONG TERM...  (Saturday through Thursday)
Issued at 315 AM CST Fri Jan 16 2026

The weather pattern remains active through the long term, although
guidance indicates there aren`t very many opportunities for
precipitation.  An upper level long wave trough persists over the
Central U.S. this weekend which will keep temperatures below normal.
 Saturday/Saturday night will be the coldest with highs as much as
20 degrees below Friday in the low 20s to around 30.  Saturday night
looks to be the coldest we`ve had since mid December with winds
becoming light and variable under a clear sky.  This will produce
excellent radiational cooling conditions and allow lows to drop into
the single digits to low teens.  The cold high pressure system moves
down to the Gulf Coast Sunday which turns low level flow over the
Mid Mississippi Valley back to the southwest. This will allow
temperatures to warm back up, but most locations will struggle to
reach the low to mid 30s due to the very cold start to the morning.

A short wave moves southeast through the Mid Mississippi Valley late
Sunday into Sunday night which drags another reinforcing shot of
cold air from the Northern Plains and Upper Midwest down into
Missouri and Illinois.  The blocking surface ridge along the Gulf
Coast keeps moisture from returning ahead of the wave, so the
forecast remains dry.  This reinforcing shot of cold air produces
another round of well below normal temperatures Monday morning
through Tuesday morning with lows in the single digits to low teens
and highs Monday struggling to reach the low to mid 20s in most
locations.  Temperatures begin to moderate Tuesday and continue to
warm Wednesday as the upper level trough shifts east.  Ensemble
guidance indicates only small variances in the temperature forecast
up to this point with IQRs mostly in the 2-4 degree range.  The
pattern shift brings more variance in the forecast for Tuesday
through Thursday.  LREF EOF patterns show increasing uncertainty in
both the amplitude and position of the long wave pattern Tuesday
through Thursday with corresponding uncertainty in surface
temperatures.  High temperature IQRs increase to 8-10 degrees during
this time frame in both the LREF and NBM.  Deterministic guidance
shows another cold front moving through late Wednesday or Wednesday
night which would bring temperatures down again, but confidence is
low out that far due to the aforementioned variance in the ensembles.

Carney

&&

.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 541 AM CST Fri Jan 16 2026

A band of very light snow/flurries is moving east to west through
the area this morning. Observations remain VFR with this band of
snow, and no change in intensity or flight conditions is expected
as the precipitation continues eastward. Expect the wind to turn
to the west and become gusty behind a weak cold front this
morning with VFR conditions continuing to prevail. Scattered
showers are expected to develop this afternoon across northeast
Missouri and west central Illinois along an Arctic cold front. The
showers will spread southeast through the afternoon into early
evening. Precipitation will likely be mostly liquid initially, but
will mix with and change to snow eventually. The heaviest snow
showers will be capable of briefly reducing the visibility to 1
mile or less with gusty winds and ceilings to 2000ft, possibly
lower. Snow showers diminish from northwest to southeast through
the evening as much colder and drier air moves into the area
behind the Arctic front. VFR conditions are expected to prevail
outside of the scattered snow showers.

Carney

&&

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

$$

WFO LSX

NWS LSX Office Area Forecast Discussion