999
FXUS63 KILX 110506
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1206 AM CDT Fri Jul 11 2025

.KEY MESSAGES...

- Daily chances for afternoon/evening thunderstorms will be seen
  through the weekend with the highest chances being on Friday
  and Saturday.

- Hot and humid conditions will be in place through the end of
  this week and again early next week. Temperatures look to trend
  cooler by the end of next week.

&&

.UPDATE...
Issued at 808 PM CDT Thu Jul 10 2025

Decreased thunderstorm chances this evening to slight chance for
most of the evening with dramatic weakening of convection that
moved from southeast IA into west central IL. Nevertheless, the
low level jet developing farther west in northern MO/southern IA
has been enhancing more thunderstorm activity in that area, and
this should extend east-northeastward into northern IL late this
evening and after midnight. How much of central IL is affected
remains in question, as a few models depict activity remaining
north of Knox, Stark, and Marshall Counties, while a few bring
activity through that area and even a county or two to the south.
Current slight chance to chance category PoPs in this area appear
to be on target, so have left forecast as-is after midnight.
Otherwise, lows near 70 appear on track for tonight.

37

&&

.DISCUSSION...
Issued at 251 PM CDT Thu Jul 10 2025

...Daily Storm Chances Through the Weekend...

A few widely scattered showers and storms have developed in east-
central Illinois along a remnant outflow boundary from an overnight
thunderstorm complex. Further northwest, a MCV from the same storm
complex is spinning over southeast Minnesota/northeast Iowa and
will be the focus for thunderstorm development over the northern
half of Illinois going into this evening. Although most guidance
keeps the majority of this activity north of our local area, a few
outlier solutions do show storms stretching as far south as I-72.
Increasing shear with the approaching MCV and moderately strong
instability could lead to a few organized storms capable of mainly
strong winds and heavy rainfall.

A low-level jet will nose into northern IL overnight, leading to
repeated rounds of heavy rainfall north of the area. Better
chances for precipitation arrive later on Friday here locally as a
shortwave impulse ahead of a parent trough spreads into the
middle Mississippi Valley Friday afternoon. A warm front is
expected to lift into north- central parts of the state by evening
with hot and humid conditions developing south of the front.
Instability will become moderately strong by afternoon with
SBCAPEs looking to approach or exceed 2000 J/kg. ~30 kt of
effective wind shear, especially near the front, will be
sufficient for thunderstorm organization, posing a risk for all
severe hazards. Storms look to fire up sometime late Friday
afternoon or early evening in our west, with activity spreading
east into the nighttime hours.

A cold front moving through the area on Saturday will bring
additional chances for precipitation through the weekend. The better
upper forcing will be displaced north of the area, though hot and
humid conditions and increasing wind shear with the front will once
again lead to marginal parameters for a few stronger thunderstorms
Saturday afternoon and evening.

Predictability becomes less certain going into next week, though a
brief break in precipitation appears possible early in the week as
an upper ridge moves overhead. Upper troughing looks to swing back
through the northern CONUS by midweek, which could lead to
additional precipitation chances later in the week.

...Hot and Humid Through the End of the Week, Again Early Next Week..

Despite daily precipitation chances, temperatures will remain hot
and humid through the end of this week with high temperatures on
Friday peaking in the low to middle 90s paired with heat indices
around 100, give or take a few degrees. Temperatures fall slightly
over the weekend with the cold front passage, but will quickly
rebound by the beginning of next week as an upper ridge slides
through the Midwest states.

Temperatures by the end of next week into next weekend look to trend
somewhat cooler than normal with the Climate Prediction Center`s 8-
14 day temperature outlook (Jul 17-23) highlighting a 33-50% chance
for below normal temperatures.

NMA

&&

.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1205 AM CDT Fri Jul 11 2025

A warm front has lifted into northern Illinois and will serve as
the main focus for storms through the period. Across central
Illinois, outside of the influence of storms, expect VFR
conditions and a modest SSW/S breeze to prevail. Gusts to around
20 kt are expected during the afternoon and evening hours. There
will be a couple potential windows of showers and storms on
station. The first will be with ongoing storms sagging south into
central Illinois late this evening. Confidence remains low in
reaching the terminals, but they may reach PIA/BMI around 06/07Z
and persist a couple hours. Another round of storms is expected
late Friday afternoon or evening and again have the highest
confidence further north at PIA/BMI.

Deubelbeiss

&&

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

$$