Severe Thunderstorm Warning 91, NWS St. Louis, MO

570 
WWUS53 KLSX 271906
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
206 PM CDT Mon Apr 27 2026

ILC119-163-MOC189-510-272000-
/O.CON.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Madison IL-Saint Clair IL-Saint Louis MO-Saint Louis City MO-
206 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 3 PM CDT FOR
SOUTHWESTERN MADISON AND NORTHERN SAINT CLAIR COUNTIES IN
SOUTHWESTERN ILLINOIS, EAST CENTRAL SAINT LOUIS COUNTY IN EAST
CENTRAL MISSOURI AND THE SAINT LOUIS CITY IN EAST CENTRAL MISSOURI...

At 206 PM CDT, a severe thunderstorm was located over Venice, moving
east at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

Locations impacted include...
  St. Louis, Jennings, Bellefontaine Neighbors, East St. Louis,
  Granite City, Centreville, Pontoon Beach, Fairview Heights,
  Collinsville, Edwardsville, Maryville, Swansea, Shiloh, Glen
  Carbon, Troy, O'Fallon, Mascoutah and Lebanon.

This includes the following State Parks...
Scott Joplin Historic Site and Horseshoe Lake State Park.

This includes the following highways...
Interstate 64 in Illinois between exits 9 and 23. Interstate 55 in
Illinois near exit 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

Tornadoes can develop quickly from severe thunderstorms. Seek shelter
immediately in an interior room on the lowest floor of a well-built
structure.

A Tornado Watch remains in effect until 900 PM CDT Monday for
portions of southwest Illinois and east central Missouri.

&&

LAT...LON 3861 9031 3874 9026 3880 9021 3882 9013
      3881 9012 3883 9011 3886 8987 3852 8977
TIME...MOT...LOC 1855Z 260DEG 24KT 3868 9027

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Elmore

777 
WWUS53 KLSX 271913
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
213 PM CDT Mon Apr 27 2026

MOC189-510-271923-
/O.CAN.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Saint Louis MO-Saint Louis City MO-
213 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR EAST CENTRAL SAINT
LOUIS COUNTY AND THE SAINT LOUIS CITY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of east central Missouri.

&&

LAT...LON 3866 9018 3875 9018 3878 9015 3880 9012
      3881 9012 3883 9011 3886 8987 3858 8979
      3864 9018
TIME...MOT...LOC 1906Z 260DEG 24KT 3869 9018

$$


ILC119-163-272000-
/O.CON.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Madison IL-Saint Clair IL-
213 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 3 PM CDT FOR
SOUTHWESTERN MADISON AND NORTHEASTERN SAINT CLAIR COUNTIES IN
SOUTHWESTERN ILLINOIS...

At 213 PM CDT, a severe thunderstorm was located over Granite City,
moving east at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

Locations impacted include...
  East St. Louis, Granite City, Madison, Venice, Fairmont City,
  Washington Park, Pontoon Beach, Hartford, Fairview Heights, South
  Roxana, Roxana, Collinsville, Edwardsville, Caseyville, Maryville,
  Glen Carbon, Troy, O'Fallon and Lebanon.

This includes the following State Parks...
Horseshoe Lake State Park.

This includes Interstate 55 in Illinois near exit 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

Tornadoes can develop quickly from severe thunderstorms. Seek shelter
immediately in an interior room on the lowest floor of a well-built
structure.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of southwest Illinois.

&&

LAT...LON 3866 9018 3875 9018 3878 9015 3880 9012
      3881 9012 3883 9011 3886 8987 3858 8979
      3864 9018
TIME...MOT...LOC 1906Z 260DEG 24KT 3869 9018

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Elmore

362 
WWUS53 KLSX 271923
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
223 PM CDT Mon Apr 27 2026

ILC163-271933-
/O.CAN.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Saint Clair IL-
223 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR NORTHEASTERN SAINT
CLAIR COUNTY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of southwest Illinois.

&&

LAT...LON 3866 9010 3875 9007 3881 8999 3886 8987
      3866 8981
TIME...MOT...LOC 1913Z 260DEG 24KT 3870 9011

$$


ILC119-272000-
/O.CON.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Madison IL-
223 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 3 PM CDT FOR
SOUTH CENTRAL MADISON COUNTY IN SOUTHWESTERN ILLINOIS...

At 223 PM CDT, a severe thunderstorm was located over Maryville,
moving east at 35 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained spotters reported quarter size hail near Glen
         Carbon.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

Locations impacted include...
  Pontoon Beach, Collinsville, Edwardsville, Maryville, Glen Carbon,
  Troy, Kuhn and Fruit.

This includes Interstate 55 in Illinois near exit 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and has
produced large hail.

Tornadoes can develop quickly from severe thunderstorms. Seek shelter
immediately in an interior room on the lowest floor of a well-built
structure.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of southwest Illinois.

&&

LAT...LON 3866 9010 3875 9007 3881 8999 3886 8987
      3866 8981
TIME...MOT...LOC 1913Z 260DEG 28KT 3871 9006

TORNADO...POSSIBLE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Elmore

431 
WWUS53 KLSX 271931
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
231 PM CDT Mon Apr 27 2026

ILC119-272000-
/O.CON.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Madison IL-
231 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 3 PM CDT FOR
SOUTH CENTRAL MADISON COUNTY IN SOUTHWESTERN ILLINOIS...

At 231 PM CDT, a severe thunderstorm was located over Troy, moving
east at 35 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to
         roofs, siding, and trees.

Locations impacted include...
  Collinsville, Edwardsville, Maryville, Glen Carbon, Troy, Kuhn and
  Fruit.

This includes Interstate 55 in Illinois near exit 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.

Tornadoes can develop quickly from severe thunderstorms. Seek shelter
immediately in an interior room on the lowest floor of a well-built
structure.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of southwest Illinois.

&&

LAT...LON 3866 9001 3874 9000 3881 8993 3886 8987
      3866 8981
TIME...MOT...LOC 1923Z 260DEG 28KT 3872 8997

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Elmore

394 
WWUS53 KLSX 271940 RRA
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
240 PM CDT Mon Apr 27 2026

ILC119-271950-
/O.CAN.KLSX.SV.W.0091.000000T0000Z-260427T2000Z/
Madison IL-
240 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR SOUTH CENTRAL MADISON
COUNTY IN SOUTHWESTERN ILLINOIS...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. A Severe Thunderstorm
Warning still remains in effect for eastern Madison County.

A Tornado Watch remains in effect until 900 PM CDT Monday for a
portion of southwest Illinois.

&&

LAT...LON 3866 9001 3874 9000 3881 8993 3886 8987
      3866 8981
TIME...MOT...LOC 1931Z 260DEG 28KT 3873 8989

$$

Elmore

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
647 AM CDT Mon Apr 27 2026

.KEY MESSAGES...

- While periods of storms are expected through Monday morning, the most
  potent thunderstorms will occur this afternoon and evening.

- Thunderstorms this afternoon and evening will be capable of
  damaging wind gusts, large hail, and strong tornadoes.

- A period of cool, calm weather is expected mid-week through the
  weekend.

&&

.SHORT TERM... (Through Tuesday Night)
Issued at 155 AM CDT Mon Apr 27 2026

Storms across southeastern Missouri continue to butt up against an
instability gradient draped from north to south across Missouri.
The warm air advection feeding these storms will also push greater
instability slowly northeastward through this morning, though
propagation vectors will favor convection continuing to move east-
southeastward generally away from the CWA or into an unfavorable
environment. Additionally, the low-level jet refocusing across
Kansas will continue to support the downward trend in convection
across southeastern Missouri early this morning. Any linger storms
over the next couple of hours will be capable mainly of large hail,
though there is also a very low damaging wind and tornado threat for
storms that remain surface based.

Our attention turns to the storms over eastern Kansas that are
propagating eastward with the nose of the low-level jet. With the
nose of this low-level jet edging into northeastern Missouri later
this morning, the focus for these storms will spread into portions
of the CWA north of I-70. Vertical thermal profiles suggest that this
convection will be elevated, mitigating a threat of damaging wind
gusts and/or tornadoes. However, with around 40 kts of effective
shear and building MUCAPE, there is a low chance for isolated
instances of large hail.

How long this convection lingers is uncertain, although guidance
trends have been toward a lull in convective activity in the wake of
this convection and that associated with a cold front during the
late afternoon and evening. Ahead of the front, the warm sector
remains capped through much of the afternoon per a majority of
deterministic soundings. Although, any remnant outflow or
differential heating boundary from early day convection may serve as
enough of a forcing mechanism to spawn discrete convection during
the afternoon as lift from an approaching shortwave increases over
the region. If this convection does form, it will be in an
environment characterized by 2,000-2,500 J/kg of SBCAPE and roughly
50 kts of deep-layer shear. This will favor supercells capable of
all hazards, with long curved hodographs favoring strong tornadoes,
especially if storms are able to latch on to any remnant boundaries
across the CWA.

Where the environment isn't contaminated from earlier rounds of
convection, additional updrafts are expected along the cold front as
it enters the area 4-5pm. Forcing from the front paired with lift
from the shortwave will lead to numerous updrafts along the front.
While this will be occurring within a similar environment detailed
prior, the number of updrafts paired with them occurring along the
front may lead to destructive interactions and congealing into line
segments and/or clusters. While this will tend to limit a strong
tornado threat, storms will still be capable of all severe hazards.
Convection is expected to depart the CWA with the front by 9-10pm.

Even with the FROPA Monday evening, the threat for convection will
continue on Tuesday. Guidance consensus has the front stalling just
south of the CWA early Tuesday and then buckling northward as a
shortwave moves through the Central Plains and into the Midwest
through the day. This shortwave will send a subtle surface
reflection through the Mid South along the front, with a brief
period of warm air advection that will help force elevated
convection for areas mainly along and south of I-70. If the front
can move northward enough, shear profiles and instability amounts
favor supercells capable primarily of large hail across far
southeastern Missouri during the afternoon. Waning instability and
the front continuing southward will bring an end to rain chances
during the evening.

Elmore

&&

.LONG TERM... (Tuesday Night through Sunday)
Issued at 155 AM CDT Mon Apr 27 2026

Both deterministic guidance and ensemble clusters keep upper-level
troughing slowly moving eastward over the eastern CONUS through the
long range forecast period. This will maintain northwesterly flow
over the Middle Mississippi Valley through Saturday as several
rounds of high pressure pass through the region. As a result,
temperatures will run at or below climatological normals into the
weekend and mostly dry weather is expected.

Elmore

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 647 AM CDT Mon Apr 27 2026

Thunderstorms are expected at times throughout the day, impacting
all terminals. The greatest coverage of thunderstorms this morning
is expected to be across central, northeastern MO into west-central
IL impacting KCOU, KJEF, and KUIN, with lower confidence in
thunderstorms reaching the St. Louis metro terminals through early
afternoon. Another round of redevelopment will take place this
afternoon and evening with the greatest chance of severe
thunderstorms as well. These thunderstorms will be capable of hail,
strong winds, and some tornadoes. Trends will need to be monitored
for more significant terminal impacts beyond MVFR to IFR flight
conditions.

A cold front will pass through the region this evening, veering
southerly winds to northwesterly with drier conditions prevailing.
There is the potential for some post-frontal MVFR ceilings late
tonight into Tuesday morning, with the highest chance of impacts at
KUIN. However, given that confidence is low in impacts before the
end of the TAF period, VFR flight conditions are maintained for
now.

Pfahler

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
202 AM CDT Mon Apr 27 2026

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-280715-
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair IL-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
202 AM CDT Mon Apr 27 2026

This Hazardous Weather Outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Today and tonight.

Periods of thunderstorms are expected through the day into this
evening. Thunderstorms this afternoon and evening will be capable of
large hail, damaging wind gusts, and tornadoes.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

There is a chance of thunderstorms Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report wind damage, hail occurrence and
size, and tornado occurrence to NWS St. Louis.

Elmore

Preliminary Local Storm Report
National Weather Service St Louis MO
1243 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0616 AM     Hail             1 NW University City    38.68N 90.35W
04/27/2026  E1.00 Inch       St. Louis          MO   Public

            Report from mPING: Quarter (1.00 in.).

&&

MCF

Preliminary Local Storm Report
National Weather Service St Louis MO
1244 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0646 AM     Hail             1 W Jennings            38.72N 90.27W
04/27/2026  E1.25 Inch       St. Louis          MO   Public

            Report from mPING: Half Dollar (1.25 in.).

&&

MCF

Preliminary Local Storm Report
National Weather Service St Louis MO
1247 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0320 AM     Hail             2 NE Doe Run            37.76N 90.47W
04/27/2026  M2.50 Inch       St. Francois       MO   Public

&&

MCF

Preliminary Local Storm Report
National Weather Service St Louis MO
103 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1235 PM     Hail             1 NW Florissant         38.80N 90.33W
04/27/2026  E0.88 Inch       St. Louis          MO   Public

            Pea to nickel sized hail lasted about 5
            minutes.

&&

MCF

Preliminary Local Storm Report
National Weather Service St Louis MO
141 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0135 PM     Hail             1 N Chesterfield        38.67N 90.58W
04/27/2026  E1.00 Inch       St. Louis          MO   Public

&&

MCF

Preliminary Local Storm Report
National Weather Service St Louis MO
143 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0136 PM     Hail             2 WNW Town And Country  38.63N 90.51W
04/27/2026  E1.00 Inch       St. Louis          MO   Public

&&

MCF