527
FXUS63 KILX 162050
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
250 PM CST Tue Dec 16 2025

.KEY MESSAGES...

- There is a very high (80-100%) chance for widespread rain on
  Thursday. The risk for severe weather remains low (5-15%) and
  focused near and south of a Taylorville to Paris line, where
  damaging thunderstorm wind gusts could be a risk.

- Strong west winds will gust Thursday night into Friday morning
  behind a sharp cold front. There is currently a medium (50-70%)
  chance for wind gusts exceeding 45 mph.

- Manic December temperatures will persist through this weekend
  and into next week.

&&

.DISCUSSION...(through next Tuesday)
Issued at 244 PM CST Tue Dec 16 2025

Temperatures have climbed above freezing this afternoon, driven
by compressional warming from fast zonal flow across the Plains,
which is now mixing into the Midwest.

The temperature trend for tomorrow will be flat, with a weak,
dissipating cold front sagging into central Illinois overnight.
Afternoon highs will remain in the 40s, except south of I-70,
where temperatures are expected to reach the 50s due to a lack of
snow cover. A significant temperature whipsaw is expected by
Thursday, with a diffuse cold front surging back northward as a
warm front. This advance is ahead of a strong shortwave energy
system pushing across the Plains, which will send afternoon highs
into the 50s.

A healthy plume of low-level moisture will be drawn up from the
Gulf by Thursday morning as southerly winds increase ahead of a
strong cold front. Ensemble and blended guidance both maintain a
very high (80-100%) chance for rain Thursday morning through mid
afternoon, though amounts (QPF) still vary quite significantly.
These differences speak to the convective potential associated
with this frontal system. While most guidance supports between
0.25-0.75 across central and southeast Illinois, some of the
upper tails hint upwards of an inch near and south of a
Taylorville to Paris line where thunderstorms could become
focused.

The potential for severe weather across central and southeast
Illinois for Thursday remains murky. On the one hand, the synoptic
forcing for ascent is really robust; as is the background
kinematics. On the other hand, thermodynamic profiles are quite
underwhelming. This is not uncommon for this time of year, where
high-shear, low-CAPE setups can still yield meaningful severe
weather events, but on the whole, this has the look of a swift-
moving convective line with a low potential for sporadic damaging
wind gusts embedded within the line, with again, the focus near
and south of a Taylorville to Paris line.

Gusty synoptic winds will accompany this sharp frontal system,
particularly behind the cold front on Thursday night as the upper-
level disturbance pivots across the Great Lakes and the attendant
surface low deepens. Given the synoptic pattern, we are trending
toward the higher end of wind guidance for Thursday evening. The
latest 13z NBM supports a reasonable probability (50-70%) of
exceeding Wind Advisory criteria in select locations north of
I-70.

Following the cold front Thursday night, a brief shot of cold air
will move in. Recent NBM guidance supports overnight lows
dropping into the teens, with wind chill values approaching zero
for a significant portion of the area.

The erratic December pattern will persist through the weekend and
into the following week, with fast zonal flow favoring a storm
track along the U.S./Canada border. Following another brief
cooling trend this weekend, temperatures are expected to rebound
sharply, reaching 10-15 degrees above normal by the middle of next
week amid a mostly dry stretch of weather.

MJA

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1144 AM CST Tue Dec 16 2025

VFR conditions will continue today with southwest winds between 10-
15 kts. A dry cold front will move through the area tonight,
shifting winds to the west-southwest. Wind will then turn light and
variable by Wednesday morning as a ridge of high pressure slides
overhead. There is a low chance for patchy fog after 12Z with most
guidance targeting areas near the KPIA and KBMI terminals.

NMA

&&

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

$$