367
FXUS63 KILX 101753
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1153 AM CST Wed Dec 10 2025

.KEY MESSAGES...

- Strong northwesterly winds gusting 40-50 mph will accompany
  scattered rain and snow showers this morning.

- Snow will spread across much of central Illinois Thursday
  afternoon through Thursday night. There is a 50-80% chance for
  greater than 2 inches of snow along and northeast of a Macomb to
  Robinson line.

- Another surge of very cold air is expected by the end of the
  week...resulting in sub-zero apparent temperatures Friday night
  through Monday morning.

&&

.DISCUSSION...
Issued at 334 AM CST Wed Dec 10 2025

...Strong Winds This Morning...

08z/2am surface analysis shows a pre-frontal trough approaching
the Illinois River...with a cold front noted further upstream
across northern portions of Iowa/Nebraska. Once the trough swings
through the area, winds will veer to northwesterly and gust
30-40mph for the entire day. The main concern for higher gusts
sill focuses on scattered rain/snow showers along and just behind
the cold front. Models have backed off somewhat on the magnitude
of the gusts, as winds at the top of the mixed layer are generally
less than 50mph. Still think the showers will be able to mix some
of the momentum down to the surface resulting in occasional gusts
in the 40-50mph range through midday. A Wind Advisory remains in
effect for much of central Illinois accordingly. Surface
temperatures will initially be in the upper 30s and lower 40s
early this morning, but will drop into the lower to middle 30s as
the scattered showers arrive. The snow may temporarily cut
visibilities to less than 1 mile in a few spots and will likely
result in a dusting to a couple tenths of an inch on grassy
surfaces. The most widespread/significant snow showers will push
into Indiana by midday, followed by just flurries for the
remainder of the afternoon and evening.

...Snow Late Thursday...

00z Dec 10 models continue to have difficulty pinning down the
exact track of the next approaching clipper system, which is
evident on latest water vapor imagery over British Columbia. Since
the system is now on land, it will be much better sampled by both
surface and upper air observations...thus the next model cycle
should have a much better handle on the exact details. Presently
there are two distinct camps...the synoptic models such as the
ECMWF and GFS which take the system across the heart of central
Illinois and the higher-res models such as the NAM and HRRR that
track it a bit further north. Taking the middle-of-the-road model
consensus places the axis of heaviest snowfall generally along the
I-74 corridor...but this could be shifted slightly northward if
the CAMs continue their trends. As it stands right now, it appears
snow will develop across the Illinois River Valley by mid-afternoon,
then quickly spread eastward toward I-57 by sunset. The
heaviest/steadiest snow will occur during the evening, with the
precip shifting eastward and diminishing overnight. The 00z Dec 10
LREF now shows a high probability (50-80% chance) for greater
than 2 inches of snow along/north of a Macomb to Robinson line.
Given the northward shift in the track, an elevated warm layer
could lead to mixed precipitation along the S/SW edge of the main
snow band. This looks most likely to occur along/southwest of a
Rushville to Taylorville line where the latest forecast includes a
mix of snow and freezing rain.

...Bitterly Cold Conditions This Weekend...

As has been advertised for the past several days, another surge of
extremely cold air will arrive this weekend. A short-wave trough
interacting with the baroclinic zone will bring another round of
light snow to central Illinois on Saturday: however, it is still
too early to pinpoint exact accumulations. The main weather story
will be the sharply colder conditions after FROPA. High temperatures
will drop from the 30s on Friday into the single digits and teens
by Sunday. While wind-chill values will dip below zero across
parts of the area by late Friday night, the coldest period will be
Saturday night into Sunday when apparent temperatures will approach
or exceed the -15F advisory criteria everywhere north of I-70.
The extreme cold will begin to ease by Monday as boundary layer
flow becomes S/SW and afternoon temperatures rise back well into
the 20s and perhaps lower 30s in some spots.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1153 AM CST Wed Dec 10 2025

MVFR cloud conditions will continue for the balance of the next 18
hours of the TAF period. A band of snow showers will depart
 to the east of the terminal sites by 20z, with CMI the remaining
site to get the snow band. However, radar returns have shown a
weakening trend for the snowfall bands and vis drops will likely
remain above IFR. A few flurries possible out of the MVFR deck
this afternoon. Otherwise, gusty winds will be the main concern
this afternoon, with W-NW gusts to 30 KT lingering but diminishing
as evening approaches. NAM/HRRR forecast soundings continue to show
the MVFR cloud deck persisting through Thursday morning. Winds
speeds by mid-evening should drop to 12kt or less after 03z/04z,
so we kept that trend going. Ceilings tomorrow morning are
projected to increase to VFR before the end of this TAF period.

Shimon

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until noon CST today for ILZ027>031-036>038-
040>045-047>056-061-062-066.

&&

$$