144
FXUS63 KILX 191757
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1257 PM CDT Wed Aug 19 2026

.KEY MESSAGES...

- Periods of showers and a few thunderstorms are expected this
  morning, then again later this afternoon into the overnight
  hours. Damaging winds, heavy rain, and localized flooding is
  in play today.

- A persistent northwest flow will keep temperatures and
  humidity levels in check the next several days, with highs in
  the upper 70s to lower 80s.

&&

.UPDATE...
Issued at 1045 AM CDT Wed Aug 19 2026

Will continue the Flood Watch for northern half of CWA from 1
pm to 1 am tonight where pockets of a few inches of rain is
possible over areas that had 5-10 inches of rain last week into
this past weekend. SPC Day1 update this morning shifted the
marginal risk of severe storms north of I-74 to now include
entire CWA, with large hail the main threat from I-74 north from
mid afternoon into this evening. There is a 5-14% risk of
damaging winds south of I-74 from mid afternoon into early
overnight while the tornado threat is over far southern IL south
of Wayne, Edwards and Wabash counties. Latest radar shows a few
showers lingering over central and southern parts of Clay,
Richland and Lawrence counties and moving eastward. Otherwise
much of central IL has been dry this morning. A short wave trof
over central/eastern SD into east NE will track toward the IA/IL
border by mid evening and pass se of CWA by late tonight. At the
surface a cold front was over northern/nw IL to near the IA/MO
border will move se into the IL river valley late afternoon as
pass through rest of CWA during tonight. Airmass gets more
unstable during the afternoon as CAPES rise to 1500-2000 j/kg
along with some wind shear. Scattered convection to develop over
central IL during mid/late afternoon and track se into southeast
IL during this evening. Latest CAMs still differ with their
convective solutions with some weight given to HRRR model. Highs
today in the lower 80s and muggy dewpoint in the lower 70s.

&&

.DISCUSSION...
Issued at 211 AM CDT Wed Aug 19 2026

Today will be a brief return to the active weather. The CAMs are
showing a narrow band of showers and/or thunderstorms setting up in
a west-east orientation across central IL, potentially where the
flooding and heavy rain occurred last week. Timing looks to be mid
afternoon for this band (20z Weds to 06z Thu). WPC has introduced a
slight risk ERO for today for all of ILX CWA. PWATs won`t be as high
as they were last week, but forecast soundings are suggesting 1.7-
2.0 inch values in place. Those same soundings have a long, skinny
CAPE profile. LPMM shows pockets of 2-5 inches locally in the
vicinity of the band. A Flood Watch will be in effect from 18z today
to 06z tonight for the northern half of the CWA.

Along with that narrow band, there could be a convective complex
that moves south of I-72, with the greatest severe risk in southern
IL. There is some uncertainty on if the complex will reach as far
north as I-72. The HRRR (00z) is the most bullish, with the complex
riding along and south of I-72 from 00z-08z this evening/overnight.
The 00z NAMNest is the opposite, depicting a much drier, less active
solution. The 00z RRFS agrees on the west-east oriented line setting
up in central IL but has the later complex missing the CWA off to
the south in southern IL. SPC has a marginal risk for severe weather
in place for areas along and south of I-74 for the activity later
today with damaging winds as the main threat.

Thursday is looking to be dry and quite pleasant. Then, additional
chances for rain return Friday into Saturday. A dry start to the new
week as a high pressure develops over the Great Lakes region Sunday.
Most people will likely remain dry or see minimal rainfall amounts
after today for the extended forecast. Pleasant August temperatures
are in store for the next week, with upper 70s to 80s for highs and
60s for lows.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1250 PM CDT Wed Aug 19 2026

Scattered convection is forecast to develop during mid/late
afternoon and continue through this evening, and early overnight
se of the IL River with MVFR conditions possible. There is also
a chance of IFR condtions with thunderstorms with heavier rains
later this afternoon into this evening. A weak east/west trof
was just south of PIA and near BMI early this afternoon with
east to NE winds near 5 kts north of this boundary and south to
SW winds near 5 kts south of the boundary. Main cold front over
northern IL to push southward into the IL river valley/PIA late
afternoon and thru rest of central IL during this evening,
keeping convection chances going for several hours. We have MVFR
vsbys possible overnight into early Thu morning from patchy fog
after the convection chances end. Winds to stay fairly light
next 24 hours under 10 kts and veer NE during tonight into Thu
morning.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for ILZ027>031-036>038-
041>046-048-053.

&&

$$

KEY MESSAGES...Copple
UPDATE...07
DISCUSSION...Copple
AVIATION...07