Severe Thunderstorm Warning 267, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
609 AM CDT Wed Jun 17 2026

.KEY MESSAGES...

- A dangerous severe weather outbreak is projected for for
  central IL today, capable of strong/intense tornadoes
  (EF2-EF3+ damage), damaging wind gusts of 75+ mph, and 2+ inch
  hail.

- Heavy rainfall rates will create a risk of localized flash
  flooding today. There is a Flood Watch out for the areas along
  and north of a Fulton County to McLean County line from 7am to
  10pm.

- Strong, non-convective gradient winds are anticipated this
  afternoon, with widespread southwest gusts near 50 mph,
  particularly for areas near and south of I-72. A Wind Advisory
  will be in effect from 12pm to 7pm.

&&

.DISCUSSION...
Issued at 307 AM CDT Wed Jun 17 2026

Bottom Line Up Front: Stay weather aware all day long today and know
where your safest shelter is when/if a warning is issued for your
location today. An outbreak of severe weather is expected later
today.

SPC has maintained a moderate risk (level 4 of 5) with an enhanced
risk (level 3 of 5) over (basically) the rest of the forecast area.
A warm front will push north, lifting better moisture (dewpoints in
the 70s and PWATS ~2 inches) into central and southeastern IL. A
morning round of convection will travel along and north of the warm
front associated with the strong LLJ this morning. If a supercell
can latch onto the warm front, tornadoes can be possible. Otherwise,
large hail and damaging winds are the concern for the morning round.
This round will enter the northern part of the forecast area by 13z
(8am) and will travel east across the state. There is some
uncertainty of how far south that area of storms will make it but
some guidance is now suggesting as far south as I-70. There is some
overlap in timing with the afternoon "big show". The early round
will be exiting the east/southeast counties by ~20z (4pm), which is
about the time the line of storms will be developing in western IL.

Some uncertainty on how far north the warm front will get still
exists. Guidance is still showing it lifting somewhere between I-74
and I-80. If the warm front doesn't get as far north as I-80, then
the moderate risk threat could possibly be pushed further south for
the cold frontal passage and associated thunderstorms in the
afternoon from 20z-05z (3pm-12am). The environment will be very
volatile and capable of strong/intense tornadoes (EF2-EF3+ damage),
damaging wind gusts of 75+ mph, and 2+ inch hail. CAPE values 2000-
3000 J/kg, insane amount of effective bulk shear values (60-70
knots), and SRH 0-1 km of ~250-450 m2/s2. Mid level lapse rates are
more than sufficient for large to very large hail (7.6-8.1 C/km).
Supercells are the expected mode through most of the event this
afternoon into evening, but may begin to evolve into a fast moving
linear system as it nears exiting the southeastern counties. The
supercells have the perfect environment to be long-lived. These
storms are going to be moving very fast, with storm motions nearly
due east at 50-60 knots.

WPC has kept an excessive rainfall high-end slight risk for central
and southeastern IL today, but our northern most counties have been
clipped by the moderate risk area. PWATs of 1.8-2.1 inches are
forecast. The storms today would likely have torrential rain within
them, but will be moving fairly fast, which would hopefully help
curb the flooding threat for most places. With many rivers/streams
already at or near flood and saturated soils, flooding could become
a concern through the event. There is a Flood Watch out for the
areas along and north of a Fulton County to McLean County line from
12z to 03z (7am-10pm) today. Remember, turn around, don't drown!

Outside of the severe weather today, there are very strong winds
associated with this system. There is a Wind Advisory in place from
Schuyler County to Vermilion County from 18z to 00z (1pm-7pm)
today. Southerly winds will gust to 35-45 mph during that time.

After today, it looks like we get two days of a break. Friday and
Saturday appear to be pleasant with highs in the upper 70s to mid
80s and plenty of sunshine. Additional rain chances return to the
forecast for Sunday into Monday.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 609 AM CDT Wed Jun 17 2026

VFR conditions will prevail at all sites for the start. However,
two rounds of showers/storms will move across each site next
16hrs. First round will be in morning and will have TEMPO at
at all sites and MVFR ceilings within the TEMPO group. Vis will
be around 3sm. After a brief break in the afternoon, the second
around moves through all sites in the afternoon to early
evening. Will have TEMPO group for all sites and MVFR ceilings
and vis for when storms move through. After line of storms moves
through, ceilings should return to VFR.

Winds will become southeasterly this morning with gusts of
20-25kts. Afternoon winds become southwesterly with gusts
pushing 35-40kts at all sites. Once storms and front moves
through, winds become westerly with gusts around 20-25kts.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through this evening for ILZ027>031-036>038.
Wind Advisory from 1 PM this afternoon to 7 PM CDT this
evening for ILZ040>057-061>063-066>068-071>073.

&&

KEY MESSAGES...Copple
DISCUSSION...Copple
AVIATION...Auten/Copple

Hazardous Weather Outlook
National Weather Service Lincoln IL
511 AM CDT Wed Jun 17 2026

ILZ027>031-036>038-040>057-061>063-066>068-071>073-181100-
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-
511 AM CDT Wed Jun 17 2026

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

.DAY ONE...Today and tonight.

Two rounds of severe thunderstorms will move through the area
today into tonight. There is a moderate risk (level 4 of 5) that
these storms will be severe. The risks are for strong and damaging
tornadoes, damaging winds of 60-75 mph with some pockets of winds
over 75 mph, and large hail over 2 inches. Flash flooding is also
possible due to storms producing up to 2 inches of rainfall in a
short amount of time.

Southwest winds will also be quite gusty outside of the
thunderstorms, with gusts of 35 to 50 mph across the whole area.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

River flooding is ongoing for portions of central IL. Please refer
to the latest flood statements for details.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed this morning north of I-70
and then again this afternoon into this evening across the whole area.

Expected storm motion is toward the east to southeast around 50-60
mph.

Auten