803
FXUS63 KILX 030443
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1043 PM CST Tue Dec 2 2025

.KEY MESSAGES...

- Bitterly cold conditions will arrive Wednesday night through
  Thursday night...with potentially record-breaking low
  temperatures at or slightly below zero by Friday morning.

- A fast-moving system will bring another period of light snow to
  the region this weekend. The 12z NBM indicates a 20-30% chance
  of snowfall exceeding 1 inch along and north of a Macomb to
  Tuscola line.

&&

.SHORT TERM... (Tonight through Wednesday)
Issued at 252 PM CST Tue Dec 2 2025

As high pressure shifts into the Ohio River Valley and boundary
layer winds become southwesterly, the persistent low cloud cover
that has plagued central Illinois today will gradually begin to
erode from SW to NE tonight into Wednesday morning. At the same
time, the slightly warmer air advecting over the cold/snow cover
will likely lead to fog development...especially east of I-55.
While CAMs are not particularly bullish with visby reductions, the
HRRR/RAP/GFSLAMP all hint at fog across the E/SE KILX CWA. Given
what happened last night into this morning, have opted to include
fog mention everywhere along/east of I-55 accordingly. After any
early morning fog dissipates, SW winds will continue to bring
milder air into the region...resulting in afternoon highs climbing
above freezing. The warmest readings will be across Clay,
Richland, and Lawrence counties where the snow cover is thinnest
and where partial sunshine will occur...leading to readings
climbing into the upper 30s. By afternoon, a strong cold front
will approach from the northwest. Given the lack of deep-layer
moisture, am not expecting much precip with FROPA late Wednesday
afternoon/evening. Will carry chance PoPs for a few snow-showers
along/north of I-72 during the afternoon...then along/south of
I-70 Wednesday night. Little to no snow accumulation is expected.
Once the front passes, winds will veer to northwesterly and
temperatures will plummet into the single digits north of I-70 and
into the teens south of I-70 by Thursday morning.

Barnes

.LONG TERM... (Thursday through Next Tuesday)
Issued at 252 PM CST Tue Dec 2 2025

Canadian high pressure will settle into the Midwest on Thursday,
bringing decreasing winds and plenty of sunshine. However with the
heart of the cold airmass overhead, high temperatures will
struggle to rise through the teens over the snow cover. Radiational
cooling Thursday night will lead to the coldest readings of the
winter season thus far. The latest guidance suggests lows bottoming
out in the single digits everywhere north of I-70...with a few
spots dropping below zero north of I-72. If these projected
numbers are realized, record lows for December 5 will be broken at
Peoria, Lincoln, and Springfield.

The extreme cold will be short-lived however, as temperatures
quickly moderate back into the upper 20s and lower 30s for the
remainder of the forecast period. Will need to keep an eye on a
pair of weak systems that will skirt through the region during
that time. The first is slated for late Saturday into Sunday,
while the second will be in the vicinity by late Monday/Tuesday.
Models have not resolved either system very well at this
point...with the 12z ECMWF showing the first wave pushing into
central Illinois on Sunday...and the GFS taking the track further
south across Missouri into southern Illinois. Given the high
degree of track uncertainty, have only mentioned low chance PoPs
(20-40%) Saturday night into Sunday. As an early projection, the
12z NBM shows a low probability (20-30% chance) of over 1 inch of
snow along/north of a Macomb to Tuscola line. This will likely be
changed as the track forecast becomes better defined over the next
couple of days.

Barnes

&&

.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1042 PM CST Tue Dec 2 2025

Late this evening and overnight, MVFR/IFR stratus mainly between
007-011 persists along and east of I-55 but should slowly
continue to erode overnight into Wednesday morning. SSW winds
around 9-12 kt are expected overnight, then will slowly veer to
the west then northwest during the afternoon as a slow moving cold
front sags into the region. MVFR/IFR ceilings will return along
and behind the cold front, and there is a chance (30%) for light
precip with the front. There remains uncertainty on the precip
type, but both snow and drizzle will be possible with surface
temps hovering near the freezing mark much of the afternoon.

Deubelbeiss

&&

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

$$