Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

034
FXUS63 KILX 132003
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
203 PM CST Tue Jan 13 2026

.KEY MESSAGES...

- Cold and windy conditions develop on Wednesday behind a cold
  front with a small chance for a few rain and snow showers.

- Additional chances for snow come Thursday night through
  Saturday, potentially resulting in minor accumulations.

- Even colder air arrives this weekend with highs expected to only
  reach the teens to 20s with overnight lows in the single digits.

&&

.DISCUSSION...
Issued at 203 PM CST Tue Jan 13 2026

Upper analysis depicts a large upper trough over Canada nosing into
the Upper Midwest. An expansive area of cloud cover stretches from
the central Plains into the middle Mississippi Valley out ahead of a
southward advancing cold front. Breezy southwest winds with gusts up
to 30 mph are common out ahead of the front, which has allowed
temperatures to warm into the upper 40s to 50s. The front will work
through the area tonight, passing through mostly dry. A few spotty
showers may develop near/south of I-70 late tonight, but chances of
that occuring are quite low (20%).

Northwest flow sets up behind the cold front for Wednesday, bringing
much colder air to the region, especially by afternoon when
temperatures fall into the 20s to low 30s. The colder air paired
with northwest winds gusting up to 35 mph will send wind chills into
the teens. Although moisture will be limited through Wednesday,
large-scale ascent under cyclonic flow aloft may support a few snow
showers or flurries through the day, or sprinkles where temperatures
remain warmer longer in the south. Little to no snow accumulation is
expected. More meaningful snow accumulations are expected to our
northeast and east where lake-effect snow will target north-central
Indiana through Wednesday night.

Additional chances for snow come Thursday night through Saturday as
a couple shortwaves track south in the northwest flow aloft. Light
snow accumulations are possible with each passing wave, with
guidance suggesting a 40-60% chance for over 1 inch across our north
with the Thursday night-Friday wave. More notably, a colder push of
air arrives over the weekend with forecast highs only expected to
only reach the teens to 20s and wind chills falling below zero. The
colder weather and active pattern looks to stick around through at
least the early to middle parts of next week as northwest flow
remains locked in aloft.

NMA

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1145 AM CST Tue Jan 13 2026

VFR conditions will prevail through this evening across the
central IL airports, before MVFR ceilings arrive during overnight
into Wednesday morning with passage of a cold front. Mid and high
clouds will stream across central IL with ceilings as low as
8-12k ft at times mainly along I-74 TAF sites. A cold front
currently over the upper MS river valley to pass southeast across
central IL during overnight and to bring MVFR ceilings of 2-3k ft
arriving between 08Z-10Z. Breezy WSW to SW winds into mid
afternoon with gusts 20-27 kts and diminishing to around 10 kts
around sunset out of the west. Winds will then veer to NW and
increase to 12-18 kts with gusts 22-27 kts after FROPA overnight
(starting at PIA between 07-08Z and CMI and DEC around 10Z) and
NNW winds around 20 kts and gusts 28-33 kts after 14-15Z Thu.

07

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$