220
FXUS63 KILX 160508
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1208 AM CDT Sun Aug 16 2026

.KEY MESSAGES...

- Flooding continues across portions of central IL in a corridor
  from Fulton and southern Knox County to Vermilion County due
  to 4 to 7 inches of rain that fell overnight.

- Additional clusters of thunderstorms are likely tonight into
  Sunday morning, with isolated afternoon thunderstorms possible
  Sunday afternoon. Storms have the potential to produce locally
  damaging winds. SPC has a marginal (level 1 of 5) risk of
  severe weather.

- The heat and humidity remain a concern this weekend, with the
  hottest conditions south of I-70.

&&

.DISCUSSION...
Issued at 156 PM CDT Sat Aug 15 2026

In the wake of widespread thunderstorm activity this morning,
heat has once again been tempered over much of the area with
some late afternoon recovery expected to bring temperatures back
up to the low 90s by afternoon in a corridor from Jacksonville
to Robinson, with heat index likely to reach around 105 south of
I-70 as a warm front lifts northward through the area. Mid to
upper 80s can be expected to the north.

A few showers remain in this frontal zone, where perhaps a few
thunderstorms could develop this afternoon as diurnal
destabilization gradually takes place.

Tonight, a cold front will approach from the northwest, with
warm advection ahead of the front promoting another cluster or
two of thunderstorms. Areas of significant precipitation are
possible, although much less likely than last night. The
location of any heavy precipitation swaths remains too uncertain
for a Flood Watch at this point, but we will continue to
evaluate any corridors for potential Watch issuance. If expected
heavy precipitation corridors line up well with last night`s
heavy precipitation from Fulton to Vermilion County these would
be favorable for renewed flooding. 12Z high-res average model
guidance points to a 1.5 to 1.5 inch corridor north of Peoria
and Bloomington, although there remain considerable run-to-run
and model-to-model discrepancies. SPC continues a Marginal Risk
for locally damaging winds with thunderstorms both tonight and
Sunday as these storms move across central IL and some afternoon
thunderstorms as diurnal destabilization takes place and the
cold front lingers over the southeast half of central IL.

A couple of dry days are forecast Monday and Tuesday behind
Sunday`s front, then another cold front midweek will bring the
next chance for thunderstorms.

Temperatures will remain quite warm and humid for central IL as
2 inch precipitable water values keep dewpoints well into the
70s and highs reach the 80s, to lower 90s south of I-70. A Heat
Advisory continues for areas south of I-70 until Sunday evening
as heat index values will near 105 each afternoon until then.
Highs will be in the 80s across the area Monday through
Tuesday, then the midweek front will continue to lower
temperatures for late in the week, with some upper 70s possible.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1208 AM CDT Sun Aug 16 2026

Another round of TSRA is expected late tonight, with the highest
probabilities shifting south to KSPI-KDEC-KCMI where TEMPO
groups are forecast and PROB30 farther north. A period of MVFR
ceilings is favored at KPIA-KBMI Sunday morning. Light southwest
winds tonight will veer west to northwest on Sunday with the
passage of a cool front.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 AM CDT this morning for ILZ027>031-
036>038-043>046.
Heat Advisory until 10 AM CDT this morning for ILZ066>068-
071>073.

&&

$$

KEY MESSAGES...Copple
DISCUSSION...37
AVIATION...25