Severe Thunderstorm Warning 312, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
545 PM CDT Fri Jul 3 2026

.KEY MESSAGES...

- A Heat Advisory is in effect Saturday for much of central and
  southeast IL.

- Isolated severe storms may develop this evening. While
  widespread severe weather is unlikely, any storm could produce
  localized torrential rainfall and brief, damaging wind gusts.

- A front will push through the region on Sunday, bringing a
  welcome end to the heat wave. Cooler, less humid, and dry
  conditions are forecast Monday through Wednesday.

&&

.DISCUSSION...
Issued at 230 PM CDT Fri Jul 3 2026

High Heat and Humidity...

The Extreme Heat Warning for CWA goes until 7 pm today with
dangerous heat indices peaking from 100-110, highest along and
southeast of a Macomb to Pontiac line where less convection has
occurred so far today. The Heat Advisory from 11 am to 7 pm on
Saturday has been expanded northward to include the rest of the
CWA except for Knox, Stark and Marshall counties. Some
convection that affected areas nw of the IL river past 1-2 hours
has cooled temps and heat indices over Knox, Stark and Marshall
counties but starting to heat back up with Galesburg heat index
up to 97F and Lacon heat index up to 96F and Heat indices may
warm back up to near 100F late this afternoon over northern 3
counties. We are forecasting highs back to around 90F to lower
90s Saturday with afternoon heat indices peaking from 100-105,
highest in southeast IL. Heat indices still around 100F in
southeast IL on Sunday afternoon while low to mid 90s from I-72
north. We may need to have another heat advisory Sunday
afternoon for southeast IL due to the duration of this heat wave
since this past Sunday June 28th.

Convective Potential & Severe Risks...

Severe Thunderstorm Watch was posted this afternoon until 7 pm
over northeast IL from LaSalle, Livingston, Ford and Iroquois
counties northeast. More widespread thunderstorms, with some
strong to potentially severe have been in northeast IL with a
few strong cells earlier passing through eastern Marshall and
northern Woodford counties between 120-2 pm with gusty winds and
possible small hail. Current radar mosaic shows isolated cells
nw of the IL river and along a St Louis to Taylorville to
Decatur to Danville line. More convection was over southern
Indiana into western KY and far southern IL. SPC day1 outlook
has marginal risk of severe storms, with slight risk north of a
Canton to Bloomington line for this afternoon and into this
evening. Primary severe wx risk is damaging winds (15%) with 5%
risk of large hail in slight risk area over northern CWA. Very
unstable airmass with ML CAPES of 3-4k j/kg while weak effective
bulk shear values less than 25 kts over all but far northern 3
counties where its 25-30 kts from Galesburg to Lacon north.

Latest CAMs show increasing convection chances into central IL
late evening and overnight while southeast IL appears to be dry
during that time frame. WPC Day 1 ERO has marginal risk of
excessive rainfall over northern/nw CWA this afternoon and
tonight with high tropical PWATs of 1.75-2 inches.

Outflow boundaries from convection going into tonight to get
further south into our CWA on Saturday and will likely see more
convection fire up along these boundaries Sat afternoon in very
unstable tropical air mass, similar to todays air mass. Some
CAMs even show some bands of convection affecting parts of CWA
Sat morning, and more convection developing and moving se Sat
afternoon/evening. SPC Day2 outlook keeps marginal risk of
severe storms over CWA on Sat for damaging winds, mainly
afternoon into mid evening. WPC Day2 ERO has marginal chance of
excessive rainfall over CWA on Sat into Sunday. Convection
chances to continue on Sunday with best chances in southeast IL
where WPC Day3 ERO has marginal chance of excessive rainfall.
SPC Day 3 outlook keeps slight and marginal risk of severe
storms se of IL and Indiana.

Next Work Week...

The cold front pushing southeast through southern IL and into nw
KY during Monday may still produce 20-30% chance of showers and
possible thunderstorms over se part of CWA, with the 30% pops in
southeast IL, se of a Danville to Shelbyville line. Cooler highs
in the low to mid 80s on Monday and still rather muggy but lower
dewpoints in the upper 60s/lower 70s. Dry weather is expected
Monday night with seasonable lows in the mid to upper 60s. We
have just slight chance of convection on Tue afternoon in
southeast IL closer to a frontal boundary lingering in nw KY and
southeast MO. GEM model appears too aggressive with a weak
upper level low/trof and its widespread showers over IL on Tue.
GFS and Ecmwf models show an upper level ridging starting to
push eastward toward the MS river valley and into IL. Seasonable
highs in the mid 80s Tue with dewpoints 65-70F. Dry weather
again Tue night into Wed morning over CWA with small chances of
convection in southeast IL Wed afternoon. Highs in the upper 80s
Wed with dewpoints in the upper 60s/lower 70s. We have chance
of showers/thunderstorms across area on Thu into Friday as
frontal boundary lifting ne from MO as warm front on Thu and
then cold front pushing se into central or nw IL on Friday.
Highs in the upper 80s to near 90F on Thu and mid to upper 80s
next Friday and muggy dewpoints 70-75F.

The Climate Prediction Center (CPC) 8-14 Day Outlook for July
11-17 has 35-40% chance of above normal temperatures over IL
with precipitation trending near normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 545 PM CDT Fri Jul 3 2026

Medium confidence in two periods of scattered thunderstorms
that could affect the central IL terminals, one tonight, and
another Saturday afternoon. Confidence on any terminal being
impacted is low, so limited mention to PROB30 for both time
periods. Outside of TSRA, VFR conditions and S-SW winds
near/under 10 kt will be common.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM CDT this evening for
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
Heat Advisory until 7 PM CDT Saturday for ILZ029-031-036>038-
040>057-061>063-066>068-071>073.

&&

KEY MESSAGES...07
DISCUSSION...07
AVIATION...25

Hazardous Weather Outlook
National Weather Service Lincoln IL
234 PM CDT Fri Jul 3 2026

ILZ027>031-036>038-040>057-061>063-066>068-071>073-041100-
Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean-Schuyler-
Mason-Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard-Scott-
Morgan-Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar-Shelby-
Cumberland-Clark-Effingham-Jasper-Crawford-Clay-Richland-Lawrence-
234 PM CDT Fri Jul 3 2026

This Hazardous Weather Outlook is for central Illinois, east
central Illinois, southeast Illinois and west central Illinois.

.DAY ONE...Tonight.

Heat index values will be 105 degrees through early evening today.
As a result, there is a high risk of heat-related illness in
sensitive individuals and those without access to effective cooling.

Isolated to scattered thunderstorms are possible this afternoon and
evening. A few may be severe with damaging wind gusts around 60 mph,
one inch hail, and locally heavy rain.

Moderate flooding continues along portions of the Illinois River
from Havana to Beardstown.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Heat index values will peak around 100 to 103 degrees Saturday
afternoon.

Scattered thunderstorms will be possible again Saturday. There is a
low risk (5-15% chance) of scattered damaging wind gusts with the
strongest cells. In addition, a few storms will be capable of
torrential downpours and localized flash flooding.

Additional thunderstorms are possible Sunday though Thursday. The
severe weather risk looks to lower for Sunday through Tuesday, but
remains more uncertain later in the week.

Moderate flooding will continue Saturday along the Illinois River
from Havana to Beardstown, but is expected to fall into minor
flooding category over the weekend. Minor flooding continues next
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

Expected storm motion is toward the east-northeast around 25 mph.

37

Special Weather Statement
National Weather Service Lincoln IL
121 PM CDT Fri Jul 3 2026

ILZ030-031-031900-
Marshall-Woodford-
121 PM CDT Fri Jul 3 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MARSHALL AND NORTH
CENTRAL WOODFORD COUNTIES THROUGH 200 PM CDT...

At 121 PM CDT, Doppler radar was tracking a strong thunderstorm over
Washburn, or 8 miles southeast of Lacon, moving northeast at 30 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Minonk, Toluca, Washburn, Wenona, Varna, and La Rose.

This includes Interstate 39 between mile markers 28 and 40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Lincoln.

&&

LAT...LON 4093 8905 4092 8894 4087 8936 4100 8938
      4111 8914 4110 8905
TIME...MOT...LOC 1821Z 246DEG 24KT 4093 8930

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Geelhart

Special Weather Statement
National Weather Service Lincoln IL
422 PM CDT Fri Jul 3 2026

ILZ066-032145-
Effingham-
422 PM CDT Fri Jul 3 2026

...A STRONG THUNDERSTORM WILL IMPACT WESTERN JASPER...SOUTHEASTERN
SHELBY...SOUTHWESTERN CUMBERLAND...NORTHERN CLAY AND EFFINGHAM
COUNTIES THROUGH 445 PM CDT...

At 422 PM CDT, Doppler radar was tracking a strong thunderstorm near
Altamont, or 7 miles southwest of Effingham, moving east at 15 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Effingham, Altamont, Teutopolis, Watson, Dieterich, Beecher City,
Edgewood, Mason, Shumway, Montrose, Heartville, and Effingham County
Airport.

This includes the following highways...
 Interstate 57 between mile markers 143 and 168.
 Interstate 70 between mile markers 79 and 104.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3922 8880 3922 8847 3917 8847 3917 8836
      3891 8836 3891 8880
TIME...MOT...LOC 2122Z 250DEG 14KT 3906 8867

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

25