474
FXUS63 KILX 310041
AFDILX

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

.KEY MESSAGES...

- Light to moderate showers will track across central Illinois
  through Sunday, bringing beneficial rainfall with little to no
  flooding impacts. Chances 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.

&&

.UPDATE...
Issued at 741 PM CDT Fri Oct 30 2026

Showers have been persistent from southeast Iowa to about
Peoria, then into east central Illinois. Overall, high-res
models have been struggling with this activity, but this
appears to be lined up with an 850-700 mb theta-e gradient seen
in the latest RAP guidance. This gradient is expected to
pivot northeast through the night, with rain chances becoming
highest closer to the I-80 corridor by 3-4 am. While the
forecast has been updated a couple times for current rain trends,
some more substantial updates across the northern CWA will be
made soon to hit the rain chances harder.


&&

.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 /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 615 PM CDT Fri Oct 30 2026

Scattered showers will continue moving across central Illinois
early this evening, but with time, will become more concentrated
just north of KPIA. Have seen some brief drops in visibility to
2-3SM, though this occurrence has been becoming less frequent.
Overall, ceilings are expected to be in the 10kft vicinity
through Saturday afternoon. Northeast winds of 8-10 knots will
gradually trend more toward the east-southeast through the
period.

&&

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

&&

$$

KEY MESSAGES...Deubelbeiss
UPDATE...Geelhart
DISCUSSION...Deubelbeiss
AVIATION...Geelhart