799
FXUS63 KILX 030453
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1153 PM CDT Tue Jun 2 2026

.KEY MESSAGES...

- Low humidity and seasonable to slightly above normal
  temperatures will continue through tomorrow, with highs in
  the low to mid 80s.

- A pattern change will occur late in the week, resulting in
  increasing humidity and storm chances (30-60%) Friday into
  next week. Afternoon heat indices may climb into the 90s at
  times.

&&

.DISCUSSION...
Issued at 102 PM CDT Tue Jun 2 2026

***** DRY AND WARM NEXT FEW DAYS *****

18z surface analysis reveals a 1028mb high over the Upper Great
Lakes, which is maintaining dry easterly flow over central and
southeast Illinois early this afternoon. This dry airmass has once
again allowed for efficient radiational warming, resulting in
temperatures already in the 80s (near the 90th percentile of model
guidance for highs) as of 1pm. This dry, seasonably warm pattern
will continue into tomorrow, though winds will start to blow from
the southeast during the afternoon as that surface high shifts
southward into the Ohio Valley.

***** SUMMERLIKE HUMIDITY, STORM CHANCES BEGIN FRIDAY *****

By Thursday, winds will begin to blow from the south-southwest as
the surface high shifts into the southeast states and ridging begins
to break down over our neck of the woods. This will gradually bring
Gulf moisture into the region, allowing dewpoints to climb well into
the 60s - highest across west-central Illinois where the Low
Resolution Ensemble Forecast (LREF) system even gives a 20-40%
chance for 70 or higher - by Friday evening. This will foster
sufficient instability (EPS mean MUCAPE ~1000 J/kg) to fuel
thunderstorms, though it remains unclear whether forcing associated
with a weak midlevel disturbance will be enough to overcome the
capping inversion apparent on forecast soundings. As additional weak
disturbances ripple through the region into early next week,
thunderstorm chances will linger, though again the lackluster
forcing makes it tricky to know if, where, and when storms will
form. Given weak shear, GEFS/EPS mean PWATs around 1.5-1.75" (above
the 90th percentile of ILX raob climatology), and a deep (>10kft)
warm cloud layer, any storms will be efficient rain producers,
making this weekend a "feast or famine" scenario for needed rain.

By early next work week, substantial model differences become
evident in the synoptic pattern, making the forecast increasingly
nebulous. Nonetheless, the general trend is for summer-like
humidity and warmth. The National Blend of Models (NBM)
advertises daily highs/lows in the upper 80s/60s with 20-40%
storm chances Monday through Wednesday (June 8-10th).

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1152 PM CDT Tue Jun 2 2026

VFR conditions prevail through the period, with scattered cirrus
present. Winds will generally be less than 10 kts, turning from
easterly to start the period to southeasterly by 15-18z.

&&

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

&&

$$

KEY MESSAGES...Bumgardner
DISCUSSION...Bumgardner
AVIATION...Erwin