834
FXUS63 KILX 031105
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
605 AM CDT Thu Sep 3 2026

.KEY MESSAGES...

- Extreme Heat: An Extreme Heat Warning is in effect through 7
  pm Friday across central and southeast IL, and extended
  through 7 pm Saturday from Schuyler, Menard, Sangamon, Shelby
  and Crawford counties southwest. High heat and humidity to
  push peak heat index values to around 105F or higher. Highs
  may reach 100F (30-70% chance per NBM) from Springfield to
  Robinson southwest today and Friday. Heat indices still peak
  from 100-105F on Saturday afternoon.

- Isolated Severe Storm Potential: While dry conditions dominate
  the next few days, there is a low risk (under 20% chance) for
  isolated thunderstorm from mid afternoon until sunset today
  and Friday mainly from I-74 northeast. There is a 20-30%
  chance of thunderstorms overnight Friday night into Saturday
  as a backdoor cold front moves in. Any storm that develop
  could become severe with localized strong winds or hail.

&&

.DISCUSSION...
Issued at 345 AM CDT Thu Sep 3 2026

The main weather story continues to be the week long heat wave
that we are experiencing through Saturday. We continued the
Extreme Heat Warning across the CWA through 7 pm Friday for
heat indices peaking around 105 or higher. Extended the Extreme
Heat Warning until 7 pm Saturday for sw 1/3rd of CWA from
Rushville to Springfield to Robinson sw for heat indices still
approaching 105F Sat afternoon. The remainder of CWA may need
also need a heat headline on Saturday especially if backdoor
cold front moves in slower since we currently are forecast heat
indices 100-105F over central/ne CWA. The NWS HeatRisk is in the
Extreme Category (level 4 of 4) for much of CWA today and
Friday, and Major Category (level 3 of 4) from I-74 sw on
Saturday with Extreme Category just sw of CWA. Cooling Centers
over IL are listed at... keepcool.illinois.gov
Today and Fridays temperatures and humidity levels similar to
yesterday with highs in the mid 90s to near 100F (warmest sw
CWA) with dewpoints in upper 60s to mid 70s (highest n/ne CWA)
and afternoon heat indices 100-110F. SW winds actually a bit
lighter today and Friday than past few days so lighter winds
providing less relief from the heat. Highs Saturday slightly
cooler ne CWA in lower 90s, while mid to upper 90s over sw half
of CWA and upper 90s in southeast IL. Heat indices still
reaching 100-105F Sat afternoon and possibly higher from
Springfield to Robinson south/sw.

Springfield reached 100F yesterday and just one degree from the
record high. The last time Springfield got that hot was July 31,
2012. Lawrenceville airport has reached 101 past two days. Both
Springfield and Lawrenceville to make a run for the century run
again today and Friday.

A strong 593-595 decameter subtropical 500 mb high from the mid
MS river valley into the Carolinas will stay near IL (se of IL)
through Friday and continue the very hot and humid airmass over
the area. The best chance of convection today through Fri
evening will be north/ne of CWA closer to a frontal boundary
near the southern Great Lakes and upper Ohio river valley, and
disturbances moving se from ND/MN across the Great Lakes region
and ne Ohio river valley. We have less than 20% chance of
convection from mid afternoon until sunset from I-74 ne today.
MUCAPEs rise to 2000-3000 j/kg over ne CWA while 0-6km Bulk
Shear values rise to 20-30 kts by late afternoon from I-72
north. Bulk wind shear is weaker around 20 kts on Fri afternoon
though more unstable with MUCAPES 2500-3500 j/kg and highest in
ne CWA. Our pops are still below 20% on Friday but still could
see very isolated convection appear from mid Fri afternoon until
sunset over ne CWA. Then 20-30% chance of thunderstorms
overnight Fri night into Sat with highest pop ne CWA as backdoor
cold front moves into central IL during Saturday. SPC day1
outlook has marginal risk of severe from from Canton to
Champaign and Danville north from mid afternoon until sunset for
mainly gusty winds though hail may also occur. SPC Day2 outlook
has marginal risk of severe for mainly wind over all but far sw
CWA overnight Fri night. SPC Day3 Outlook has marginal risk of
severe storms over eastern CWA generally from highway 51 east on
Saturday afternoon for gusty winds and hail. WPC ERO keeps
marginal risk of excessive rainfall ne of CWA next few days
though can not rule out an isolated storm with very heavy rains
with PWATs 1.5-1.75 inches.

The strong mid/upper level subtropical ridge retrogrades west
into the Great Plains early next week giving IL a break from the
impressive heat/humidity though still warmer than normal with
highs in the mid 80s ne CWA and upper 80s/lower 90s sw CWA. The
strong 500 mb ridge building back into IL Tue/Wed and likely
bringing the high heat and humidity back to the area with highs
in the 90s and afternoon heat indices approaching 100F (highest
on Wed).

The Climate Prediction Center (CPC) 8-14 Day Outlook for Sep
10-16th has 65-75% chance of above normal temperatures over
central and southeast IL with precipitation trending near
normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 605 AM CDT Thu Sep 3 2026

VFR conditions will prevail at all sites next 24hrs. Skies will
be clear this morning, but then a few mid clouds around 8kft
will form over the sites. By evening, isolated convection could
develop well north of the sites, so some mid clouds around 12kft
will be possible at PIA and BMI, while cirrus will be the only
thing to affect SPI, DEC, and CMI. Skies should return to being
mostly clear late tonight. Winds will be south to southwest
through the period with light winds now and again this evening.
Daytime winds will be around 10kts.

&&

.CLIMATE...
Issued at 440 PM CDT Mon Aug 31 2026

Record high temperatures this week:

Location       Thu 9/3     Fri 9/4
========       ========    ========
Bloomington... 102/1913    100/1925
Champaign..... 99/2011    100/1954
Charleston.... 100/1925     98/1925
Danville...... 99/1913    101/1954
Decatur....... 102/1913    103/1913
Jacksonville.. 101/2011    103/1899
Lincoln....... 100/1913    102/1954
Olney......... 105/1925    103/1954
Paris......... 101/1913    104/1954
Peoria........  99/1913     98/2015
Springfield... 100/2011    100/1954

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM CDT Friday for ILZ027>031-
036>038-041>046-053>057-063.
Extreme Heat Warning until 7 PM CDT Saturday for ILZ040-
047>052-061-062-066>068-071>073.

&&

$$

KEY MESSAGES...07
DISCUSSION...07
AVIATION...Auten
CLIMATE...07/Geelhart