171
FXUS63 KILX 301843
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
143 PM CDT Fri Oct 30 2026

.KEY MESSAGES...

- Light to moderate showers will track across central Illinois
  this afternoon through Sunday, bringing beneficial rainfall with
  little to no flooding impacts. Localized amounts of 0.50 to
  0.75 inches remain possible northwest of the Illinois River
  today, but the chance of exceeding an inch over the weekend is
  under 10% areawide.

- Daily rain chances and mild temps with highs in the upper 60s
  and 70s continue into the first half of next week, with a 60%
  chance for rainfall to exceed one inch west of I-57 by
  Wednesday night.

- A cold front will pass through the region Wednesday night
  into Thursday, bringing blustery north winds and dropping
  daytime temperatures back into the 50s and possibly 40s in
  spots.

&&

.DISCUSSION...
Issued at 128 PM CDT Fri Oct 30 2026

NEAR TERM /THROUGH TONIGHT/...
This afternoon, a broad surface high stretches from the
Canadian Prairies into the Great Lakes. Isentropic ascent and
mid-level warm air advection west of the ridge axis will drive
showers and a few storms with the initial focus across northern
Missouri into Iowa and west central Illinois early this
afternoon, but spreading east across portions of central and
east central Illinois through the remainder of the day. Weak
elevated instability rooted near 800 mb will support shallow
convection; however, poor mid-level lapse rates will keep
equilibrium levels near or below the ice-growth zone,
suppressing lightning potential. HREF LPMM shows the potential
for localized rainfall swaths of 0.50 to 1.00 inch, especially
northwest of the Illinois River Valley, but rainfall amounts
will taper quickly further east with little to no measurable
precip expected east of I-55.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Broad isentropic ascent across the 300-315K surfaces will
further expand east across the Mississippi Valley over the
weekend, bringing additional rain showers Saturday and Sunday.
Weak mid-level lapse rates (<6.0 C/km) will continue to limit
thunderstorm activity, but moisture transport will push
precipitable water (PWAT) values up to 1.00-1.30 inches by
Sunday afternoon--exceeding the 90th percentile of GEFS model
climatology. NBM 48-hour mean QPF values average around 0.10 to
0.25 inches through Sunday night. NBM 90th percentile has
trended down but still suggests isolated pockets exceeding
0.5-0.75 inches will be possible over the weekend. NBM
probability for exceeding an inch is now less than 10% across
the forecast area for the weekend. Given the antecedent dry
conditions, any rainfall will be beneficial with negligible
impacts.

LONG TERM /MONDAY THROUGH FRIDAY/...
A closed upper-level low over the West Coast this weekend will
dig southeastward across the Intermountain West Sunday night
into the Central and Southern Plains Monday, inducing surface
cyclogenesis over Colorado and Kansas. The upper low is
projected to stall and slowly meander eastward across the
mid/lower Mississippi Valley through midweek, ejecting several
lobes of vorticity ahead of this feature and supporting daily
chances for showers and a few storms through at least the first
half of next week. NBM probabilities for reaching at least an
inch of rain in 48-hours peak around 60% west of I-57 Wednesday
evening/night. Mild temperatures in the upper 60s and 70s will
dominate early to midweek.

Timing differences between the models persist but are starting
to hone in on the surface low and attendant cold front passing
through central Illinois Wednesday night into Thursday. High
temperatures drop into the 40s and 50s in the wake of the system
under a period of blustery northerly winds. Given the continued
timing discrepancies among models, the NBM currently broad-
brushes the thermal gradient late in the week averaging out the
forecast highs in the 60s.


&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1208 PM CDT Fri Oct 30 2026

A stationary front is expected to remain just south of the
terminals with a modest easterly breeze and isolated to
scattered showers across central Illinois. VFR conditions should
prevail through the period, but cannot rule out brief MVFR
ceilings or vsby in or around showers. The thunder threat is
low, but non-zero. As we head into the evening and overnight
hours, the focus for precip is expected to shift slightly
northward favoring PIA/BMI.

&&

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

&&

$$

KEY MESSAGES...Deubelbeiss
DISCUSSION...Deubelbeiss
AVIATION...Deubelbeiss