Flash Flood Warning 37, NWS St. Louis, MO

750 
WGUS73 KLSX 212226
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
526 PM CDT Sun Jun 21 2026

ILC005-051-135-220030-
/O.CON.KLSX.FF.W.0037.000000T0000Z-260622T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bond IL-Fayette IL-Montgomery IL-
526 PM CDT Sun Jun 21 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM CDT THIS
EVENING FOR NORTHEASTERN BOND, NORTHWESTERN FAYETTE AND SOUTHEASTERN
MONTGOMERY COUNTIES IN SOUTH CENTRAL ILLINOIS...

At 526 PM CDT, Doppler radar indicated that between 2 and 3 inches of
rain have fallen. Runoff from this heavy rain is causing flash
flooding in the warning area.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Vandalia, Greenville, Ramsey, Mulberry Grove, Van Burensburg,
  Woburn, Shafter, Fillmore, Smithboro, Bingham and Bayle City.

This includes the following State Parks...
Ramsey Lake State Recreation Area.

This includes Interstate 70 in Illinois between exits 61 and 63.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3903 8933 3910 8928 3922 8925 3922 8892
      3898 8906 3887 8943

FLASH FLOOD...RADAR INDICATED

$$

Carney

915 
WGUS73 KLSX 220020
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
720 PM CDT Sun Jun 21 2026

ILC005-051-135-220030-
/O.EXP.KLSX.FF.W.0037.000000T0000Z-260622T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bond IL-Fayette IL-Montgomery IL-
720 PM CDT Sun Jun 21 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 730 PM CDT THIS EVENING FOR
NORTHEASTERN BOND, NORTHWESTERN FAYETTE AND SOUTHEASTERN MONTGOMERY
COUNTIES IN SOUTH CENTRAL ILLINOIS...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 100 AM CDT for portions of
south central and southwest Illinois.

&&

LAT...LON 3903 8933 3910 8928 3922 8925 3922 8892
      3898 8906 3887 8943

$$

Jaja

Area Forecast Discussion
National Weather Service Saint Louis MO
324 PM CDT Sun Jun 21 2026

.KEY MESSAGES...

- Damaging winds and tornadoes are possible through this evening
  across east central and southeast Missouri into southwest Illinois.

- Locally heavy rainfall is also possible through early tonight.

- Seasonably cool conditions are forecast this work week.

&&

.SHORT TERM...  (Through Late Tonight)
Issued at 324 PM CDT Sun Jun 21 2026

A remnant MCV is currently in southwest Illinois and moving
east/northeast. There has been a very slow and gradual uptick in
convection out ahead of this feature across southwest and south-
central Illinois as diurnal instability continues to increase.
Low- level shear and helicity remain quite strong, so mini
supercells may be capable of producing tornadoes. This threat will
continue at least over the next few hours as the MCV progress
through south- central Illinois.

Farther southwest, additional showers and thunderstorms are expected
to develop farther southwest along the trailing cold front. Exactly
where and when is not certain, but my best guess would be near the
Missouri-Kansas border where surface convergence is located. At
least scattered storms should develop farther northeast eventually
along the boundary, with storms moving east/southeast in time. How
organized this convection will be is also uncertain as there are a
couple of limiting factors including: 1) weak surface convergence
along the boundary and 2) modest height rises behind the MCV. In
addition, the prior storms have at least helped limit instability
slightly, with MLCAPE values of 1000-1500 J/kg. Effective shear also
decreases behind the MCV, though is still near 30 knots. A mixed
mode of convection seems most likely, with multicellular clusters,
small bowing segments, and transient supercells all possible.
Damaging winds and a tornado or two are possible through late
evening before storms begin to move out to the southeast. Locally
heavy rainfall is also possible given high precipitable water values
(~1.9"). Afternoon/evening storms are however focused farther
southwest. Storms also should be progressive, so overall I think the
flash flood threat is low and likely would be isolated to any areas
that do experience some training.

Gosselin

&&

.LONG TERM...  (Monday through Next Sunday)
Issued at 324 PM CDT Sun Jun 21 2026

(Monday - Monday Night)

Cooler weather along with northerly winds and clouds are
expected on Monday. High temperatures are only expected to reach
into the mid 70s, or about 10 degrees below normal for the date.
Lows Monday night are forecast to drop into the mid 50s to near the
60 degree mark.

(Tuesday - Next Sunday)

Not much has changed with respect to the work week forecast with
broad northwest flow aloft across the Mississippi Valley. There is
high confidence in seasonally cool temperatures with mostly dry
weather expected outside of a cold frontal passage
Wednesday/Wednesday night.

Moderating temperatures are forecast heading into next weekend with
flow aloft becoming more zonal. That means increasing
moisture/instability as well and increasing chances of showers and
thunderstorms.

Gosselin

&&

.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 until 1 AM CDT Monday 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 Boone MO-Callaway MO-
     Cole MO-Gasconade MO-Lincoln MO-Moniteau MO-Montgomery MO-
     Osage MO-Warren MO.

IL...Flood Watch until 1 AM CDT Monday 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 Calhoun IL.

&&

WFO LSX

Preliminary 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.

&&

JPG

Preliminary 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.

&&

LSJ