Severe Thunderstorm Warning 99, NWS St. Louis, MO

632 
WWUS53 KLSX 272101 RRA
SVSLSX

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

ILC001-149-MOC127-163-173-272130-
/O.CON.KLSX.SV.W.0099.000000T0000Z-260427T2130Z/
Adams IL-Pike IL-Marion MO-Pike MO-Ralls MO-
401 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR
SOUTHEASTERN ADAMS AND NORTHWESTERN PIKE COUNTIES IN WEST CENTRAL
ILLINOIS AND SOUTHEASTERN MARION, NORTHWESTERN PIKE AND NORTHEASTERN
RALLS COUNTIES IN NORTHEASTERN MISSOURI...

At 401 PM CDT, a severe thunderstorm was located over New London, or
7 miles south of Hannibal, moving northeast at 45 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...
  New London, Ilasco, Hannibal, Saverton, Ashburn, Seehorn, Hull,
  Kinderhook, New Canton, Plainville, Barry, El Dara, Richfield, New
  Hartford, Liberty and Kingston.

This includes Interstate 72 between exits 4 and 20.

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 for portions of
west central Illinois and northeast Missouri.

&&

LAT...LON 3969 9145 3991 9106 3958 9089 3948 9142
      3964 9153
TIME...MOT...LOC 2046Z 241DEG 40KT 3953 9155

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

$$

Elmore

101 
WWUS53 KLSX 272111
SVSLSX

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

ILC001-149-MOC127-163-173-272130-
/O.CON.KLSX.SV.W.0099.000000T0000Z-260427T2130Z/
Adams IL-Pike IL-Marion MO-Pike MO-Ralls MO-
411 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR
SOUTHEASTERN ADAMS AND NORTHWESTERN PIKE COUNTIES IN WEST CENTRAL
ILLINOIS AND SOUTHEASTERN MARION, NORTH CENTRAL PIKE AND NORTHEASTERN
RALLS COUNTIES IN NORTHEASTERN MISSOURI...

At 411 PM CDT, a severe thunderstorm was located 9 miles southeast of
Fall Creek, or 9 miles east of Hannibal, moving northeast at 45 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...
  Ilasco, Hannibal, Saverton, Seehorn, Hull, Kinderhook, New Canton,
  Plainville, Barry, El Dara, Richfield, Liberty and Kingston.

This includes Interstate 72 between exits 4 and 20.

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 for portions of
west central Illinois and northeast Missouri.

&&

LAT...LON 3970 9142 3991 9106 3958 9089 3955 9131
TIME...MOT...LOC 2101Z 242DEG 40KT 3961 9136

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

$$

Elmore

611 
WWUS53 KLSX 272118
SVSLSX

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

MOC127-163-173-272128-
/O.CAN.KLSX.SV.W.0099.000000T0000Z-260427T2130Z/
Marion MO-Pike MO-Ralls MO-
418 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR SOUTHEASTERN MARION,
NORTH CENTRAL PIKE AND NORTHEASTERN RALLS COUNTIES IN NORTHEASTERN
MISSOURI...

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 for a portion of
northeast Missouri.

&&

LAT...LON 3973 9137 3991 9106 3958 9089 3956 9117
      3959 9117 3960 9118 3962 9122 3962 9123
      3967 9128 3969 9132 3971 9135
TIME...MOT...LOC 2111Z 242DEG 40KT 3966 9123

$$


ILC001-149-272130-
/O.CON.KLSX.SV.W.0099.000000T0000Z-260427T2130Z/
Adams IL-Pike IL-
418 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR
SOUTHEASTERN ADAMS AND NORTHWESTERN PIKE COUNTIES IN WEST CENTRAL
ILLINOIS...

At 418 PM CDT, a severe thunderstorm was located 5 miles west of
Barry, or 14 miles east of Hannibal, moving northeast at 45 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...
  Seehorn, Hull, Kinderhook, New Canton, Plainville, Barry, El Dara,
  Richfield, Liberty and Kingston.

This includes Interstate 72 between exits 4 and 20.

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 for a portion of
west central Illinois.

&&

LAT...LON 3973 9137 3991 9106 3958 9089 3956 9117
      3959 9117 3960 9118 3962 9122 3962 9123
      3967 9128 3969 9132 3971 9135
TIME...MOT...LOC 2111Z 242DEG 40KT 3966 9123

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

$$

Elmore

916 
WWUS53 KLSX 272127
SVSLSX

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

ILC001-149-272137-
/O.EXP.KLSX.SV.W.0099.000000T0000Z-260427T2130Z/
Adams IL-Pike IL-
427 PM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING WILL EXPIRE AT 430 PM CDT FOR
SOUTHEASTERN ADAMS AND NORTHWESTERN PIKE COUNTIES IN WEST CENTRAL
ILLINOIS...

The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire. A Severe
Thunderstorm Warning still remains in effect for Adams and Pike
Counties.

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

&&

LAT...LON 3973 9137 3991 9106 3958 9089 3956 9117
      3959 9117 3960 9118 3962 9122 3962 9123
      3967 9128 3969 9132 3971 9135
TIME...MOT...LOC 2118Z 242DEG 40KT 3970 9113

$$

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
237 PM CDT Mon Apr 27 2026

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

0221 PM     Hail             4 SE Jonesburg          38.82N 91.26W
04/27/2026  E1.00 Inch       Warren             MO   Public

&&

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

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

0152 PM     Tstm Wnd Dmg     2 SW Marine             38.77N 89.80W
04/27/2026                   Madison            IL   Public

            Shed damaged.

&&

Carney

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

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

0300 PM     Tstm Wnd Dmg     5 W Winfield            38.99N 90.83W
04/27/2026                   Lincoln            MO   Emergency Mngr

            Power lines down on Ethlyn Rd.

&&

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

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

0305 PM     Hail             Old Monroe              38.93N 90.75W
04/27/2026  M0.70 Inch       Lincoln            MO   Public

&&

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

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

0245 PM     Flash Flood      1 ENE Coalton           39.29N 89.29W
04/27/2026                   Montgomery         IL   Public

            Flooded roads outside of Nokomis on E 23rd
            Rd.

&&

Carney

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

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

0256 PM     Hail             Moscow Mills            38.95N 90.92W
04/27/2026  M1.00 Inch       Lincoln            MO   Public

&&

Carney