769
FXUS63 KILX 031733
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1233 PM CDT Sun Aug 3 2025

.KEY MESSAGES...

- Smoke from wildfires will persist over central Illinois the next
  few days, though much of the time the greatest concentrations
  will remain aloft.

- Comfortable humidity levels will continue through the remainder
  of the weekend, along with below normal temperatures. Any
  precipitation should hold off until Monday or Tuesday as
  increased humidity returns. A warming trend will continue
  through the week.

&&

.DISCUSSION...
Issued at 144 AM CDT Sun Aug 3 2025

High pressure will continue to dominate the Great Lakes region
through the remainder of the weekend, promoting subsidence and
significantly reduced boundary layer moisture across central
Illinois. A persistent low-level northeast flow, reinforced by
deep mixing, will continue to produce 50-degree dew points across
most of central Illinois through this evening. The northeast winds
will also help to keep temperatures several degrees below the
climatological normal of 85-86 degrees. Highs are projected to
reach right around 80 degrees this afternoon.

Meanwhile, ongoing wildfire activity upstream will continue to
introduce smoke and haze into the region, though mainly aloft.
Despite this improvement at the surface, EPA air quality
projections continue to indicate moderate air quality pollution
across most of central Illinois today, with some spots north of
the Illinois River falling within the `Unhealthy for Sensitive
Groups` category. HRRR vertically integrated smoke fields show
some concentrations of smoke lingering into Monday with some
improvement from the south possible early next week as the ridge
over the Great Lakes shifts east allowing boundary layer flow to
veer to a southeasterly direction.

As the surface ridge axis gradually shifts eastward through the
upcoming week, dew points are expected to gradually increase,
reaching the 60s early in the week and eventually the 70s through
the second half of the week. A persistent and blocky upper ridge
will be situated over the southwestern CONUS for much of the
upcoming week, positioning central Illinois downstream within an
area of split flow. As a result, synoptic forcing will be absent
or quite weak through the upcoming week. Precipitation chances
will be largely confined to isolated to widely scattered (20-40%)
afternoon and evening convective activity, primarily driven by
diurnal heating/instability and smaller scale forcing mechanisms.

Deubelbeiss

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1232 PM CDT Sun Aug 3 2025

High pressure will remain centered near the Great Lakes today, but
begin to weaken and move east tonight allowing winds to shift from
northeasterly to southeasterly. Clouds will begin to increase
late in the period as a result of increasing moisture moving into
the area with the wind shift, but VFR conditions should continue.
Winds E-NE 7-12 kts this afternoon, decreasing to around 5 kts
overnight, then shifting to E-SE by 15Z and increasing slightly.

37

&&

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

$$