406
FXUS63 KILX 090453
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1053 PM CST Sat Nov 8 2025

.KEY MESSAGES...

- Rain becomes likely tonight. Precipitation could mix with or
  changeover to snow overnight with light snow accumulations
  possible near and north of I-74.

- Sharply colder temperatures are expected Sunday through Monday
  night. Wind chill values Monday and Tuesday mornings will drop
  into the teens.

&&

.UPDATE...
Issued at 857 PM CST Sat Nov 8 2025

Steady rain continues across the northern parts of the CWA while
scattered showers move across the central and southeast parts.
This will continue through the night, with central and southeast
parts of the CWA seeing more widely scattered precip until the low
gets past most of the area and the precip advects into the area
from the northwest. Across the north, once the low moves further
east, cooler air will push into the area and the precip will
become mixed with snow and then a gradual change over to all snow.
Due to the wet and warm ground, accumulations will remain minor
and should stay along and north of I-74. Winds also become
northwesterly and become very gusty with gust speeds around 30
mph or higher. Current forecast has a good handle on everything
and no major update is planned. However, may still make some minor
tweeks.

Auten

&&

.DISCUSSION...
Issued at 216 PM CST Sat Nov 8 2025

2 pm upper air analysis shows low pressure centered just south of
the Hudson Bay with a shortwave trough approaching the middle
Mississippi Valley. A surface low is in the process of deepening
over central Missouri with it forecast to slide east across south-
central Illinois this evening. Radar mosaic depicts precipitation
ongoing out ahead of the upper wave across Iowa/northern Missouri
and into parts of northern Illinois. Observations upstream are
showing mostly rain with a few snow reports sprinkled in.
Precipitation chances increase later this afternoon into tonight.
Although most will see rain through the overnight hours, a mix with
snow or all snow is expected with accumulating snow possible across
our northern counties. The last several runs of high resolution
models have keyed in on a narrow band of light accumulating snow
coinciding with an area of strong 700-900 mb frontogenetic banding.
The 850 mb 0 degree C isotherm looks to be right on the heels of the
fgen band, which would favor a rain/snow mix.

Although antecedent environmental conditions should limit overall
accumulations, there is a low chance (20-40%) for snow
accumulations to exceed 1 inch/hour near and north of I-74 for a a
couple of hours after midnight. With the nocturnal timing and
potential for higher snowfall rates, it should be enough to allow
light snow accumulations to occur mainly on elevated and grassy
surfaces. Mean snowfall amounts look to be around 1 inch or less,
though some higher end guidance favors a narrow corridor exceeding
2 inches north of a roughly Macomb to Hoopeston line. The chance
of this seems pretty low at this time, though if temperatures cool
quicker than forecast snow amounts may need to be increased.
Breezy northerly winds with gusts up to 35 mph overnight could
also result in significantly reduced visibility where
precipitation transitions to snow.

Better forcing shifts into Indiana by daybreak on Sunday, though
lake-effect snow showers/flurries could linger into the first half
of Sunday in east-central Illinois. The fetch over Lake Michigan
begins to shift to the northwest by late morning/early afternoon,
lowering chances for precipitation by afternoon. However, chances
increase once again Sunday night in east-central IL as winds turn
back to the north over Lake Michigan for a brief time.

The upper low south of the Hudson Bay will dive into the Midwest
states on Sunday with a deep trough developing over the eastern half
of the US for the start of the new week. Sharply colder
temperatures filter in Sunday through Monday night with daytime
highs only in the 30s to low 40s and overnight lows in the 20s.
Elevated winds both Monday and Tuesday nights will send wind
chills down into the teens.

Surface ridging slides across the area by midweek, turning winds to
the south and commencing a warm up. Temperatures will climb back to
the 60s to near 70 degrees by late week and persisting into next
weekend. Precipitation chances look minimal this upcoming week, with
just a few passing upper waves to tour north.

NMA

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1055 PM CST Sat Nov 8 2025

All sites will see conditions continue to deteriorate overnight
as the low pressure area moves east and lower clouds and
additional precip wraps around the low on the back side over the
TAF site. IFR conditions will be common at PIA, BMI, and CMI while
lower MVFR will be at SPI and DEC. However, as SPI and DEC
experience a mix of rain and snow, cigs could drop to below 1kft
at times. At PIA and BMI and CMI, predominate snow is possible so
have PROB30 groups for that and this could result in minor
accumulations. After the precip moves through there will be a
short break in the precip at all site during the morning hours.
However, even through guidance suggests clouds scattering out
tomorrow, other parameters show that clouds will fill back in
tomorrow in cyclonic flow and these broken clouds will be capable
of flurries through the day. Northwest winds will be the rule at
all sites tonight through tomorrow, with speeds increasing with
gusts of 25-30kts possible at all sites.

Auten

&&

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

$$