034
FXUS63 KILX 091113
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
613 AM CDT Tue Jun 9 2026

.KEY MESSAGES...

- An early season heat wave is expected today through Thursday
  across central and southeast IL. The combination of heat and
  humidity will lead to heat index values peaking between 95 and
  105 degrees each afternoon Tuesday through Thursday. Heat
  Advisories are posted for west central and southwest IL this
  afternoon and early evening. Those sensitive to heat should
  take extra precautions.

- There is a slight to enhanced risk of severe storms from I-72
  north Wednesday night, and across central and southeast IL
  Thursday afternoon/evening.

&&

.DISCUSSION...
Issued at 355 AM CDT Tue Jun 9 2026

We canceled/expired the Flood Watch at 1 am CDT across the CWA,
as convection became more widely scattered and not as heavy by
late Monday evening. The heavier and more widespread convection
should be focused east of IL and sw of CWA into this morning. Radar
mosaic at 330 am currently shows a band of convection near and
east of the IL/IN border with the heaviest cell north of
Danville. Isolated small showers were over east central IL with
Lincoln getting a light shower about an hour ago. An MCS with
large area of convection supported by a stronger sw low level
jet and high PW values of 1.7-2.1 inches was over eastern KS
into nw and west central MO and about as far east as Columbia,
MO. Patchy fog over the IL river valley especially at Galesburg
where there was some clearing of low clouds. Added patchy fog
early this over the IL river valley and should lift quickly by
mid morning.

The mid level trof was near the IL/IN border at predawn will
move eastward across the Ohio river valley today, while
mid/upper level ridge builds into IL this afternoon. Best
chances of convection to be east of IL over Indiana and sw over
MO into this morning. But moderately unstable air mass over CWA
by afternoon will keep a slight chance of showers and
thunderstorms around today especially over parts of central and
eastern IL. MLCAPES rise to 1500-3000 j/kg by mid day and
afternoon, with most unstable air over west central IL while
low-level lapse rates become steep in the afternoon. Wind shear
remains weak today so any storms that develop will be
unorganized and pulsey. SPC Day1 outlook continues marginal risk
of severe storms this afternoon into mid evening over CWA
primarily for damaging wind threat, with large hail threat just
nw of CWA. WPC day1 ERO has marginal risk of excessive rainfall
today and evening over eastern/se IL with slight risk near
Lawrence county. Latest CAMs show a narrow band of convection
affecting ne CWA this evening and lifting ne of CWA by late
tonight.

A 3 day heat wave begins today with highs today in the upper
80s to around 90F (warmest western CWA where more sunshine
expected). Dewpoints getting into the mid 70s today gives
afternoon heat indices peaking in the 95-104F range, highest
from Peoria and Springfield west. Heat Advisories are posted
this afternoon and early evening for west central and sw IL.
Muggy lows overnight in the low to mid 70s.

Mid/upper level ridge shifts east over the Ohio river valley on
Wed while a frontal boundary will stay north of IL. This will
likely be the hottest day this week with partly to mostly sunny
skies and highs in the lower 90s. Dewpoints in the low to mid
70s gives afternoon heat indices peaking near or just above
100F Wed afternoon, and higher HI readings over southern/sw IL.
The 06Z HRRR and RRFS runs show scattered convection over the IL
river valley and northern/nw CWA Wed afternoon and we have
slight chances of thunderstorms then. Moderate instability again
with MLCAPES 2500-3500 j/kg Wed afternoon into early Wed evening
over nw CWA and could see a few strong to possibly severe cells
then if they occur. SPC Day2 Outlook has slight risk from I-72
north and enhanced risk over nw part of Knox and Stark counties
for mainly Wed night period as line of strong to severe
convection tracks se into nw IL late Wed evening/overnight and
weakens by late night/early Thu morning into central IL.
Damaging winds over 75 mph possible from Canton to Lacon nw.
Large hail and tornadoes also risk, with larger than 2 inch hail
over nw Knox county. WPC Day2 ERO has marginal risk of excessive
rainfall nw of the IL river mainly for Wed night.

Models have trended a bit slower with cold front moving se into
nw IL Thu afternoon and thru central/se IL during Thu night.
This will likely bring another squall line moving se into the IL
river valley late Thu afternoon and over rest of CWA during Thu
evening. SPC Day3 outlook has slight to enhanced risk of severe
storms over CWA late Thu afternoon and Thu evening, with the
enhanced risk from Danville to Litchfield nw. All severe wx
parameters at play including tornadoes and SPC has level 1
intensity of severe storms as far se as I-70. WPC Day3 ERO has
marginal to slight risk of excessive rainfall over CWA for late
Thu afternoon/Thu night with the slight risk over nw half of
CWA.

Quieter weather expected Fri/Sat over central/se IL as weak high
pressure settles over area Fri night. Expect cooler and less
humid conditions. Highs Fri in the low to mid 80s and mid 80s on
Saturday. Dewpoints lower into the upper 50s/lower 60s Fri and
low to mid 60s on Saturday. Next wx system moving into the
region Sat night and Sunday as cold front moves thru area
overnight Sat night into Sunday morning. This returns chances
of showers and a few thunderstorms especially overnight Sat
night into Sunday along with reinforcing cooler and drier air
Sunday through Tuesday with highs in the upper 70s/lower 80s and
dewpoints getting into the mid to upper 50s early next work week.

The Climate Prediction Center 8-14 Day Outlook for June 16-22nd
has a 33-40% chance of below normal temperatures over much of
IL, and a 40-50% chance of above normal precipitation over
central and southeast IL.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 613 AM CDT Tue Jun 9 2026

Stratus deck has finally lifted to the north of KPIA/KBMI, and
ceilings at/above 5kft should prevail over central Illinois
today. Main challenge will be with timing of any convection.
High-res models have a variety of solutions for today, but not
much enough agreement between them. A couple models do hint at
some activity associated with a small-scale disturbance
currently over central Missouri, and will include a PROB30 group
for KSPI/KDEC this afternoon for this potential.

&&

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

&&

$$

KEY MESSAGES...07
DISCUSSION...07
AVIATION...Geelhart