076
FXUS63 KILX 211723
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1223 PM CDT Tue Jul 21 2026

.KEY MESSAGES...
- Brief Severe Thunderstorm Threat Today: A brief window for
  severe thunderstorms exists through mid-afternoon before a
  cold front moves out of the area. Cooler, drier air and gusty
  northwest winds will arrive this evening.
- Pleasant Mid-Week Weather: Expect calm weather with below-
  normal temperatures Wednesday and Thursday, with afternoon
  highs remaining in the mid-to-upper 70s.
- Heat Returns This Weekend: High temperatures rebound into the 90s
  by Sunday and Monday. There is a 20% chance of periodic
  thunderstorms returning late Friday into early next week.

&&

.DISCUSSION...
Issued at 1219 PM CDT Tue Jul 21 2026

Near Term Forecast...
The current surface analysis places a cold front along the I-70
corridor, with expected progression southeastward and out of
our CWA by mid-afternoon. RAP analysis continues to highlight an
unstable airmass ahead of the boundary, characterized by MLCAPE
values near 3000 J/kg and deep-layer shear profiles of 30-40
kt. Given this overlap, a brief window of opportunity for severe
thunderstorm development exists through mid afternoon before
the front exits the region. Behind the boundary, a cooler and
drier air mass is filtering into the region on gusty northwest
winds. Dew points have already begun a downward trend,
eventually bottoming out in the 50s across the northern tier of
the forecast area tonight, with ambient temperatures settling
into the 60s under mostly clear skies.

Wednesday through Friday...
The middle of the week will feature a transition to a more
tranquil regime as a robust Canadian high-pressure system
builds southeast across the Midwest. This will facilitate a
trend toward below-normal temperatures, with afternoon highs
confined to the mid to upper 70s. Dry conditions are anticipated
to prevail through Thursday night. By Friday, guidance suggests
the potential for warm air advection-driven convection
originating to our west. While confidence remains low, there is
a non-zero potential for these showers and thunderstorms to
encroach upon portions of central Illinois; however, the lack of
significant moisture return currently limits more robust PoP
inclusion.

This Weekend into Next Week...
As the surface ridge translates toward the Atlantic Coast over
the weekend, the return of low-level southerly flow will
initiate a noticeable warming trend. Temperatures are progged to
rebound significantly, with widespread 90s returning to the
forecast by Sunday and Monday. The synoptic pattern remains
anchored by northwest flow aloft, with periodic, lower-amplitude
shortwaves expected to traverse the region. These disturbances
may serve as catalysts for convective initiation, though timing
and placement remain difficult to resolve this far out. Have
capped precipitation chances at approximately 20% during this
timeframe until better agreement is reached among short-range
guidance.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1219 PM CDT Tue Jul 21 2026

A cold front has pushed across central Illinois leaving breezy
northwest winds in its wake. Expect gusts of around 20 kt to
continue through sunset this evening, then taper off overnight.
Winds will turn NE overnight, then back to northerly midday
Wednesday. VFR conditions are expected through the period.

&&

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

&&

$$

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