Area Forecast Discussion
Issued by NWS Central Illinois

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530
FXUS63 KILX 211058
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
558 AM CDT Fri Aug 21 2026

.KEY MESSAGES...

- A Slight Risk of severe thunderstorms exists this
  afternoon/evening north of a line from Beardstown to Lincoln
  to Gibson City. Hail (15%), wind (15%), and tornado (2%)
  threats will exist in this area, with lower probabilities
  further south.

&&

.DISCUSSION...
Issued at 215 AM CDT Fri Aug 21 2026

Weak high pressure over IL this morning will give way to a weak
cold front tonight along with an upper level wave. With CAPEs of
2000-3000 J/kg and shear around 30-35 kts, severe storms will
be possible late this afternoon and this evening. Expect some
discrete cells developing in northern IL/eastern IA early in the
afternoon, drifting south-southeast through central IL during
the late afternoon and evening hours. The SPC has central IL in
a Slight Risk for today (level 2 out of 5) north of a line from
Beardstown to Lincoln to Gibson City. Hail (15%), wind (15%),
and tornado (2%) threats will exist in the Slight Risk area.
Further south a Marginal Risk exists...north of a line from
Effingham to Danville, with mainly low end hail/wind (5%) threats
for this evening in this area.

Late tonight, storms will likely wind down by midnight or
shortly thereafter, with winds shifting to the northwest after
the cold front moves through the area. Expect sunny skies, light
northwest winds, and temperatures rebounding into the low 80s
during the afternoon. A few of the models have an isolated
storm or two developing in central IL on Saturday afternoon.
However, the probability is at 10% or less, so did not include
it in the forecast. Leaving out thunder for Saturday matches
SPC`s guidance as well.

Northwesterly flow aloft will continue through the weekend and
into next week. An upper level trough moving southeast across
the Great Lakes region by mid week could bring a few showers or
storms to the area. But generally expect a drier pattern along
with temps near to slightly below normal for the remainder of
the period.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 558 AM CDT Fri Aug 21 2026

Expect light winds today along with mostly clear skies. We
should see some cumulus around 4 kft this afternoon and we
still have a 30-50% chance for thunderstorms today. However, the
timing has shifted back somewhat. The last few runs of the CAMs
have pushed TS activity back to the evening or even the
overnight hours for the central IL terminals. Will shift back
the timing a bit.

&&

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

&&

$$

KEY MESSAGES...Knutsvig
DISCUSSION...Knutsvig
AVIATION...Knutsvig