498
FXUS63 KILX 300921
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
321 AM CST Sun Nov 30 2025

.KEY MESSAGES...

- Another round of accumulating snow will impact the area by
  Monday evening. There is currently a high (50-70%) chance of
  exceeding 3 inches of snow in areas north of a Taylorville to
  Champaign line. At least minor travel impacts are anticipated.

- We are entering a prolonged period of cold weather this week.
  Daily temperatures will average 15 to 25 degrees below what is
  considered normal for this time of year. Cold weather impacts
  are likely.

&&

.Discussion (through next Saturday)...
Issued at 302 AM CST Sun Nov 30 2025

Early this morning, gusty northwest winds are impacting central
Illinois, situated between a departing winter storm (1007 mb) over
lower Lake Michigan and a strong 1040 mb surface high building
into the Northern Plains. Our regional mesonet has recorded gusts
of 35-45 mph, with a few reaching 50 mph. Boundary layer winds
appear to be mixing deeper than model forecasts, a trend that may
continue past sunrise.

While a short-fused Wind Advisory was considered, an SPS was
issued instead, as only a few locations met the advisory criteria.
Winds will stay breezy this afternoon, generally 20-30 mph, but
will ease as a secondary trough moves across the Corn Belt,
pushing the winter storm further eastward into the Great Lakes.
Anticipate low clouds and scattered snow showers near and north of
I-74 into the early afternoon as this trough axis crosses into
northern Illinois. Winds will then diminish this evening as the
trough departs and high pressure moves into the Midwest.

Our focus quickly moves to Monday afternoon, when central
Illinois is expected to see another burst of accumulating snow.
This snowfall will be driven by a strengthening band of
frontogenesis (FGEN) beneath a pair of phasing jet streaks. While
the resulting upward motion (ascent) will be robust, it will also
be brief. Model guidance, both ensemble and multi-model, suggests
Quantitative Precipitation Forecast (QPF) values between 0.1 and
0.3 inches for our region. With an estimated Snow-to-Liquid Ratio
(SLR) near 15:1, the expected snowfall accumulation is 2 to 4
inches, which will likely necessitate a Winter Weather Advisory
for a good chunk of the area.

Temperatures will fluctuate between very cold and just plain cold
throughout the week as high pressure moves in and out of central
Illinois. A brief warm-up is expected Wednesday afternoon,
bringing the next chance for a good portion of the area to rise
above freezing. This warming trend is due to a southwest wind
shift ahead of a weak cold front approaching from the north. This
frontal passage may bring a few snow showers, though accumulations
are expected to be limited to a dusting. Following the front, a
short period of very cold temperatures will settle in, with high
confidence in overnight lows dipping into the single digits both
Wednesday and Thursday nights. While a Cold Weather Advisory is
currently unlikely, wind chill values are still anticipated to
fall below zero.

Another potential winter storm is on the horizon to conclude the
week, driven by a mid-level trough lifting and pivoting across the
Southern Plains. It`s not yet clear whether we will be completely
on the cold side of this one, or somewhere in the messy middle,
but it does look like enough Gulf moisture will be juiced into
this system to cause some sort of winter-weather impacts near or
just south of our area. For what it`s worth, both ensemble and
multi-model guidance support a 1 in 5 chance of snowfall exceeding
2 inches across our area by Friday night. This same guidance also
supports a low probability of freezing rain as well.

MJA

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 955 PM CST Sat Nov 29 2025

LIFR ceilings will rise to IFR over the next few hours as a cold
front sweeps east of the terminals. This will cause southwest
winds to veer west overnight and increase gusts to 25-30 kt. These
gusts will continue through Sunday morning, then gradually
diminish during the afternoon. Ceilings are forecast to rise to
MVFR late tonight into Sunday morning then persist through 00z.

25

&&

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

$$