239
FXUS63 KILX 020037
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
737 PM CDT Thu Oct 1 2026

.KEY MESSAGES...

- Multiple rounds of widespread rain will track across the
  region through Friday morning. Broad rainfall totals around
  one inch are expected, though localized heavy rain bands could
  produce isolated amounts of 2 to 4 inches.

- Temperatures drop significantly heading into the weekend,
  with highs from the mid 60s to around 70 Friday and Saturday,
  and overnight lows falling into the 40s.

- Dry conditions and seasonably cool temperatures look to
  continue next work week.

&&

.UPDATE...
Issued at 737 PM CDT Thu Oct 1 2026

A significant increase in rain coverage has been occuring over
the past couple hours. Previously a bit slow in making its
push east from the Illinois River, the leading edge has reached
I-55, with more scattered activity further east along a surface
boundary. Our evening sounding showed precipitable water values
at 2 inches, close to record territory for early October.
Rainfall rates around a half inch per hour are currently
occurring just west of I-55, though lightning activity has been
fairly non-existent recently. REFS precipitable water
projections show the 2+ inch PW`s persisting over central
Illinois for central Illinois for a few more hours, gradually
shifting toward the I-70 corridor by midnight. While 1-hour
flash flood guidance near I-55 is in the 2-2.5 inch range, any
heavy rain with training echoes may lead to some ponding of
water in poor drainage areas.

&&

.DISCUSSION...
Issued at 145 PM CDT Thu Oct 1 2026

A cold front located near the Mississippi River this afternoon will
continue to shift eastward overnight as an upper level trough over
the region progresses eastward, ingesting an upper level low and
remnant moisture from former tropical system Polo. 12Z soundings in
the southern Plains reflect over 2 inches of precipitable water,
which lends credence to localized accumulations of rainfall of
2 to 4 inches shown in a few high-res models by Friday morning.
Amounts of this range would require nearly stationary corridors
of multiple rounds of showers or thunderstorms (training).
Nevertheless, most areas can expect one half to one inch
amounts. A few thunderstorms will also be possible through
tonight given low values of CAPE forecast, although recently
have not detected any lightning from showers around the IL River
and westward.

Precipitation should come to an end by sunrise from I-55
northwestward, but could linger past noon from I-70 southward.
Nevertheless, dry conditions will be in place across the area by
Friday night as high pressure builds into the region from the
northwest. High pressure will remain dominant through next week,
although a few dry cold fronts could modulate temperatures.
Highs should reach only mid 60s to around 70 Friday and Saturday,
warm a bit for Sunday with lower to mid 70s, then cool back to
around 70 for Monday and Tuesday following a front Sunday.
Temperatures warm a bit Wednesday and Thursday to mid and upper 70s.
After lows still fairly mild in much of the area tonight, with upper
50s to mid 60s east of I-55 and lower to mid 50s to the west, lows
should generally be seasonably cool with 40s to around 50 the next
several days.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 622 PM CDT Thu Oct 1 2026

Initial wind shift from S/SE to NW is currently about to enter
KDEC and will reach eastern Illinois early this evening, while a
more substantial increase in speeds occur later this evening as
winds become north. While showers in eastern Illinois have been
more scattered thus far, a more substantial area of rain will
shift southeast across the terminals through the evening,
lingering well past midnight in eastern Illinois. This will be
accompanied by a period of IFR ceilings of 600-900 feet, and
potential for heavier showers reducing visibility below 2 miles.
VFR ceilings should return at KPIA around 08-09z, reaching
KDEC/KCMI toward 12-13z or so.

&&

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

&&

$$

KEY MESSAGES...37
UPDATE...Geelhart
DISCUSSION...37
AVIATION...Geelhart