A convective complex moved through the region during the day on June 21st. Though it remained sub-severe for most of its life, the complex did intensify in south-central Illinois where it produced tornadoes, wind damage, and flash flooding.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LSX wrote it up.
A convective complex moved through the region during the day on June 21st. Though it remained sub-severe for most of its life, the complex did intensify in south-central Illinois where it produced tornadoes, wind damage, and flash flooding.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS St. Louis, MO wrote its last area forecast discussion before the first event at Jun 21, 11:30 AM CST, 2 hours 49 minutes earlier. Its key messages:
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1230 PM CDT Sun Jun 21 2026
.KEY MESSAGES...
- Thunderstorms are anticipated across the area this morning
through tonight. Some storms may be strong to severe this
afternoon/evening with the main threats being tornadoes,
damaging winds, and large hail.
- Locally heavy rainfall potentially leading to flash flooding is
also expected this morning into tonight.
- Seasonably cool conditions are forecast this week.
&&
.SHORT TERM... (Through Late Monday Afternoon)
Issued at 221 AM CDT Sun Jun 21 2026
An active period of weather is forecast from early this morning into
tonight, including the risk of severe weather and heavy rainfall
potentially leading to flash flooding in some locations. Currently,
as of 06z (1am), a large mesoscale convective vortex (MCV)
encompasses much of the state of KS, with a broad area of showers
and thunderstorms extending northeastward into northern MO. The
strongest portion of this activity, which is being maintained by a
strong (50+kt) low-level jet, is currently tracking eastward across
south-central KS, essentially following the instability gradient
that extends eastward into southern MO. All of this activity has
been initiated by a mid-level shortwave trough that is traversing
the Great Plains, which has also sparked the formation of a lee-side
surface cyclone that is positioned to the west of the MCV.
As the MCV pushes eastward into central/northeast MO around 12z
(7am) this morning, a strong LLJ will continue to provide abundant
moisture transport and low-level shear to maintain convection.
However, with marginal instability early this morning (<500 J/kg
MUCAPE) across much of the area, the greatest threat with stronger
thunderstorms is expected to be marginally severe wind gusts up to
60mph, which would be favored along any bowing/surging segments that
may form. The primary threat is still forecast to be heavy rainfall
potentially lead to flash flooding. Forecast soundings indicate that
a warm cloud layer >12,000ft will be present, favoring warm rain
processes. Also with PWATs near 2", thunderstorms will be efficient
rainfall makers, and capable of rainfall rates in the 1-2+"/hr
range. The greatest threat for flash flooding this morning appears
to be across central/northeast MO and west-central IL as the center
of the MCV should be focused in those areas.
By the early afternoon, the MCV is forecast to be sliding across
east-central MO into western IL. An intensification of thunderstorms
is possible as instability increases throughout the day. Also,
within the MCV and vicinity of the surface cyclone, low-level
shear/SRH becomes enhanced, leading to an increasing threat for
tornadoes. With rich moisture and elongated low-level hodographs,
storm clusters with embedded supercells and surges with mesovortices
will be possible, especially if low/mid-level instability increases.
As a result, the greatest threats anticipated this afternoon/evening
are tornadoes along with damaging winds. This includes a potential
for strong tornadoes if supercells remain relatively organized and
sustained across the area.
Additionally, an outflow boundary in the wake of the MCV along with
the cold front associated with the surface cyclone will serve as
localized enhancements of surface convergence. Therefore, with
sufficient instability, it is expected that additional thunderstorm
development will happen near these features, perhaps somewhere from
central-southeast MO in the afternoon. With sufficient deep-layer
shear (>30kts), there is the potential for organized development
along these boundaries. Tornadoes, damaging winds, and large hail
will all be possible with this convective activity, but remains
dependent on the magnitude of instability that is available. Lastly,
the threat for heavy rainfall will continue, with the threat area
potentially shifting to southern portions of the area where the
better convective coverage is forecast to be in the late
afternoon/evening. Also, with the mean flow becoming increasingly
parallel to the forecast boundary later tonight, training of
thunderstorms may enhance the threat for heavy rainfall and flash
flooding.
Guidance reveals the surface cyclone lifting northeastward tonight,
with the cold front clearing to the southeast by tomorrow morning,
bringing an end to the threat for severe weather and flash flooding.
An additional subtle mid-level shortwave is progged to traverse the
area on Monday and may support some lingering post-frontal showers
across southern portions of the area early Monday. With low-level
CAA taking hold on Monday along with post-frontal stratus, a cooler
day is forecast with highs in the 70s across the entire area.
Peine
&&
.LONG TERM... (Monday Night through Saturday)
Issued at 221 AM CDT Sun Jun 21 2026
Northwesterly flow aloft will take hold over the region Tuesday into
the end of the week, resulting in a stretch of largely dry
conditions along with seasonably cool temperatures. A mid-level
shortwave near the Great Lakes Wednesday into Thursday may send a
cold front our way. This feature would bring our best chances for
rain sometime mid-week, with 20-40% chances being revealed by the
latest LREF. Generally, highs in the upper 70s/lower 80s and lows in
the low/mid 60s look to prevail, which is about 5-10 degrees below
climatological normals. This is supported well by the LREF, which
has narrow 3-5 degree temperature IQR spread through Friday.
By the end of the week, long-range deterministic guidance indicates
an additional shortwave aloft moving into the Midwest. Currently,
this appears to be the next best chance for more rainfall, sometime
from late Friday through next weekend. A signal for a warming trend
also appears next weekend, however this is also when LREF
temperatures IQR spreads increase to 10 degrees, indicating more
variability.
Peine
&&
.AVIATION... (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1227 PM CDT Sun Jun 21 2026
Showers and thunderstorms are expected to move out of the metro
St. Louis terminals over the next 2 hours. Additional development
is expected later this afternoon, but may be just south of both
central Missouri and St. Louis terminals. The actual cold front
should move through from northwest to southeast through tonight,
with winds veering from the southwest to the northwest and
eventually north/northeast through the period. Low stratus is also
forecast behind this front, with a period of IFR ceilings likely.
Gosselin
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through late tonight for Franklin MO-Saint Charles
MO-Saint Louis City MO-Saint Louis MO.
Flood Watch through Monday morning for Crawford MO-Iron MO-
Jefferson MO-Madison MO-Reynolds MO-Saint Francois MO-
Sainte Genevieve MO-Washington MO.
Flood Watch until 7 PM CDT this evening for Audrain MO-Boone MO-
Callaway MO-Cole MO-Gasconade MO-Lincoln MO-Moniteau MO-
Montgomery MO-Osage MO-Pike MO-Warren MO.
IL...Flood Watch through late tonight for Bond IL-Fayette IL-Greene
IL-Jersey IL-Macoupin IL-Madison IL-Montgomery IL.
Flood Watch through Monday morning for Clinton IL-Marion IL-
Monroe IL-Randolph IL-Saint Clair IL-Washington IL.
Flood Watch until 7 PM CDT this evening for Adams IL-Brown IL-
Calhoun IL-Pike IL.
&&
WFO LSXPreliminary Local Storm Report
National Weather Service St Louis MO
242 PM CDT Sun Jun 21 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0225 PM Non-Tstm Wnd Dmg 1 SW Warson Woods 38.60N 90.40W
06/21/2026 St. Louis MO Trained Spotter
Power lines down near North Woodlawn and
Manchester Road.
&&
JPGPreliminary Local Storm Report
National Weather Service St Louis MO
318 PM CDT Sun Jun 21 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0225 PM Non-Tstm Wnd Dmg 1 SW Warson Woods 38.60N 90.40W
06/21/2026 St. Louis MO Trained Spotter
Corrects previous non-tstm wnd dmg report
from 1 SW Warson Woods. Power lines down
near North Woodlawn and Manchester Road.
Downed lines caught cars in a car dealership
on fire on Manchester and Woodlawn.
&&
LSJThe Evansville,IN radar (KVWX), 130 km away, was scanning. The volume nearest the first event began at 20:18 UTC.
5 thunderstorm wind, 4 tornado, 2 flash flood. Local standard time, as filed.
A severe thunderstorm brought strong winds which broke large tree branches. One fell onto a cabin.
A chaser photo taken around 3:50 on hwy 51 shows a tornado directly in front (south) of a tree line along the Fayette/Marion county line. Just to the west of the tornado in that image, an NWS storm survey found minor (EF-0) damage along the county line.
A chaser photo taken around 3:50 on hwy 51 shows a tornado directly in front (south) of a tree line along the Fayette/Marion county line. Just to the west of the tornado in that image, an NWS storm survey found minor (EF-0) damage along the county line.
A severe thunderstorm brought strong winds leading to multiple trees downed. Power lines were downed along CR 1900N near N 1300E.
Between 2 and 3 inches of rain fell in a very short time. This led to flash flooding, particularly near the town of Ramsey. Roads were covered in up to 4 feet of water and at least one family was displaced from their home.
Between 3 and 5 inches of rain fell in a short period of time. This led to water over several roadways including at least 2 vehicles that got stuck in flood waters.
NWS storm survey found very clear tornadic damage (EF-1) east of Kinmundy, with supporting video showing a multi-vortex tornado in that location.
A severe thunderstorm brought strong winds that downed tree limbs. There were 2 cabins were damaged by the fallen limbs.
Video from around 1/2 mile south of the Marion/Fayette county line shows a weak tornado to the north of a treeline along the county line. Just to the west of the tornado in that video, NWS storm survey found minor (EF-0) damage slightly north of the county line.
Strong thunderstorm winds caused a moving police car to be blown off the road on Highway 51 north of Sandoval.
A thunderstorm produced scattered straight line wind damage to trees in this location.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2026Every state in 2026This day in weather historyThe tornado archive for Illinois, 2026Warnings in Illinois, June 2026
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1348995, 1334175, 1334176, 1348996, 1349055, 1349061, 1334177, 1348997, 1334178, 1348998, 1348999.