Severe Thunderstorm Warning 147, NWS St. Louis, MO

563 
WWUS53 KLSX 162136
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
436 PM CDT Sat May 16 2026

ILC051-162146-
/O.CAN.KLSX.SV.W.0147.000000T0000Z-260516T2200Z/
Fayette IL-
436 PM CDT Sat May 16 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR SOUTHEASTERN FAYETTE
COUNTY...

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

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT
Saturday for a portion of south central Illinois.

&&

LAT...LON 3869 8901 3871 8885 3882 8876 3883 8873
      3883 8870 3848 8870 3848 8897 3847 8905
      3847 8911
TIME...MOT...LOC 2103Z 271DEG 18KT 3882 8882 3866 8901 3856 8924

$$


ILC121-162200-
/O.CON.KLSX.SV.W.0147.000000T0000Z-260516T2200Z/
Marion IL-
436 PM CDT Sat May 16 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 5 PM CDT FOR
CENTRAL MARION COUNTY IN SOUTH CENTRAL ILLINOIS...

At 436 PM CDT, severe thunderstorms were located along a line from 9
miles east of Farina to 10 miles south of Salem, or along a line from
23 miles northeast of Salem to 9 miles east of Centralia, moving east
at 20 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.

This severe thunderstorm will be near...
  Omega, Stephen Forbes Station and Salem around 440 PM CDT.
  Helm around 455 PM CDT.

Other locations impacted by the severe thunderstorm include Iuka,
Cartter, Walnut Hill and Kell.

This includes the following State Parks...
Stephen A. Forbes State Recreation Area.

This includes Interstate 57 in Illinois between exits 109 and 116.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. These storms are 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.

&&

LAT...LON 3869 8901 3871 8885 3882 8876 3883 8873
      3883 8870 3848 8870 3848 8897 3847 8905
      3847 8911
TIME...MOT...LOC 2103Z 271DEG 18KT 3882 8882 3865 8896 3848 8918

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

$$

BRC

082 
WWUS53 KLSX 162141
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
441 PM CDT Sat May 16 2026

ILC121-162200-
/O.CON.KLSX.SV.W.0147.000000T0000Z-260516T2200Z/
Marion IL-
441 PM CDT Sat May 16 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 5 PM CDT FOR
EASTERN MARION COUNTY IN SOUTH CENTRAL ILLINOIS...

At 441 PM CDT, severe thunderstorms were located along a line from 11
miles east of Farina to 10 miles south of Salem, or along a line from
24 miles northeast of Salem to 10 miles south of Salem, moving east
at 20 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Emergency management reported. Widespread tree damage and
         hail between quarter and golf ball size has been reported at
         multiple locations within Marion County.

IMPACT...People and animals outdoors will be injured. Expect hail
         damage to roofs, siding, windows, and vehicles. Expect wind
         damage to roofs, siding, and trees.

This severe thunderstorm will be near...
  Omega, Stephen Forbes Station and Salem around 445 PM CDT.
  Helm around 455 PM CDT.

Other locations impacted by the severe thunderstorm include Kell,
Iuka, Cartter and Walnut Hill.

This includes the following State Parks...
Stephen A. Forbes State Recreation Area.

This includes Interstate 57 in Illinois near exit 109.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. These storms have produced 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.

&&

LAT...LON 3866 8895 3871 8881 3882 8876 3883 8874
      3883 8870 3848 8870 3848 8897 3847 8901
      3847 8905 3848 8905
TIME...MOT...LOC 2136Z 271DEG 18KT 3882 8861 3865 8875 3848 8897

TORNADO...POSSIBLE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.50 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

BRC

168 
WWUS53 KLSX 162149
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
449 PM CDT Sat May 16 2026

ILC121-162200-
/O.CON.KLSX.SV.W.0147.000000T0000Z-260516T2200Z/
Marion IL-
449 PM CDT Sat May 16 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 5 PM CDT FOR
SOUTHEASTERN MARION COUNTY IN SOUTH CENTRAL ILLINOIS...

At 449 PM CDT, severe thunderstorms were located along a line from 8
miles north of Helm to near Helm, or along a line from 15 miles east
of Salem to 15 miles southeast of Salem, moving east at 30 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Emergency management reported. Widespread tree damage and
         hail between quarter and golf ball size has been reported at
         multiple locations within Marion County.

IMPACT...People and animals outdoors will be injured. Expect hail
         damage to roofs, siding, windows, and vehicles. Expect wind
         damage to roofs, siding, and trees.

This severe thunderstorm will be near...
  Helm around 450 PM CDT.

Other locations impacted by the severe thunderstorm include Iuka.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from
windows. These storms have produced 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.

&&

LAT...LON 3861 8887 3866 8878 3870 8870 3848 8870
      3848 8891
TIME...MOT...LOC 2141Z 271DEG 23KT 3862 8873 3852 8880 3848 8882

TORNADO...POSSIBLE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.50 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

BRC

389 
WWUS53 KLSX 162201
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
501 PM CDT Sat May 16 2026

ILC121-162211-
/O.EXP.KLSX.SV.W.0147.000000T0000Z-260516T2200Z/
Marion IL-
501 PM CDT Sat May 16 2026

...SEVERE THUNDERSTORM WARNING HAS EXPIRED FOR SOUTHEASTERN MARION
COUNTY IN SOUTH CENTRAL ILLINOIS...

The storms which prompted the warning have moved out of the area.
Therefore, the warning has been allowed to expire. However, gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT
Saturday for a portion of south central Illinois.

&&

LAT...LON 3861 8887 3866 8878 3870 8870 3848 8870
      3848 8891
TIME...MOT...LOC 2149Z 271DEG 23KT 3862 8867 3851 8873 3848 8876

$$

BRC

Area Forecast Discussion
National Weather Service Saint Louis MO
121 PM CDT Sat May 16 2026

.KEY MESSAGES...

- Additional scattered thunderstorms are possible (20-30%) this
  afternoon and evening. The main risk is large hail and damaging
  winds.

- Additional thunderstorm chances return early this week with a
  more widespread severe weather threat possible along a slow
  moving cold front Monday night into Tuesday.

&&

.SHORT TERM...  (Through Late Sunday Night)
Issued at 112 PM CDT Sat May 16 2026

An upper level trough has moved onshore over the western CONUS,
with a surface low over the Central High Plains and a warm front
extending into Iowa. There was a secondary warm front/convergence
zone draped along the I-70 corridor this morning, and this is
what kicked off this morning's storms. These storms have reinforced
a baroclinic zone across the CWA, with temps in the upper 60s
across our north and pushing 80 in our south.

As we move through the afternoon and into the evening, additional
thunderstorm development will be largely focused to the north and
west of the area, near the primary warm front. However, the above
baroclinic zone may serve as a secondary focus for convection this
afternoon, and a few of the most recent runs of the HRRR are hinting
at that possibility. Given the weak forcing along this feature and
lack of deep forcing, I don't expect widespread convection, but a
few additional thunderstorms remain a possibility. If these storms
do develop, MUCAPE around 2,500 J/kg and effective bulk shear around
30 kts may allow few of these storms to become strong enough the
support large hail or damaging winds.

The stronger convection expected to develop near NW MO should
grow upscale and track to the ENE through the night. While
previous runs of high-res guidance has largely kept these storms
to our north, a few of the CAMs have begun pushing them a bit
further south into our area. These storms may also pose a marginal
threat for damaging winds and large hail as they diminish and
move across NE MO and west-central IL this evening.

Tomorrow, longwave troughing will amplify over the western CONUS,
reinforcing deep southwesterly flow over the Mid-Mississippi Valley.
Given the lack of any focused forcing for ascent, it appears likely
that we'll see little to no precipitation and notably less cloud
coverage than today. The increased insolation, coupled with the
above deep southerly flow, should push temperatures quite a bit
higher tomorrow.

BSH

&&

.LONG TERM...  (Monday through Next Saturday)
Issued at 112 PM CDT Sat May 16 2026

A compact shortwave will eject from the western CONUS trough on
Monday, spurring cyclogenesis over the Central Plains. The resultant
forcing for ascent from central KS through Iowa and into the Great
Lakes will force another round of thunderstorms, largely to the north
and west of our forecast area. These areas will also feature strong
dynamics, which coupled with a very unstable airmass, will result
in scattered/numerous strong to severe thunderstorms. The atmosphere
will also be rather unstable over the Mid-Mississippi Valley, but
without any focused forcing, anything more than widely scattered
thunderstorms appear unlikely. Additionally, much more modest
wind shear on our CWA will limit storm organization and severe
potential. Our best chance for severe weather through Tuesday
morning will be tied to whether the storms that develop to our
northwest are able to grow upscale and persist as they advance
into our forecast area.

A cold front associated with Monday's surface low is expected to
push through the region on Tuesday. Ahead of the front, instability
should build into the 1000-2000 J/kg range, which coupled with the
front, will result in the best chance for thunderstorms in the
extended forecast. While the SPC convective outlook continues to
highlight our area on Tuesday, I do see a couple of factors that may
limit the potential for severe thunderstorms. First of all, the best
deep layer dynamics are expected to remain well to the north of our
forecast area, limiting deep layer shear to around 30kts ahead of
the front. Secondly, it's unclear how storms from Monday night and
Tuesday morning will unfold across the area and whether the
atmosphere can recover before the frontal passage. Even if we do
recover, the above wind shear would be only marginally supportive
for severe thunderstorms. With that, the 15% contour from SPC seems
appropriate, but I would not expect that to increase much, barring a
notable change in the models.

The above cold front should push the deep moisture our of our
region, with the vast majority of guidance keeping dewpoints below
60 through the end of the week. Persistent weak zonal flow aloft
may open the door for a few weak shortwaves to move through the
region, but the lack of moisture will keep precipitation chances
limited.

BSH

&&

.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1216 PM CDT Sat May 16 2026

The primary aviation concern are the ongoing storms near the STL
metro and over NE MO and west-central IL. The storms near STL are
rapidly decaying, but are still hanging onto some lightning. With
that, I've just included an hour of -TSRA to cover the lightning
threat, but no notable visby reduction as precipitation should be
relative light.

Further north, more robust convection has persisted generally just
to the south and west of KUIN. Those storms should move over that
terminal at some point in the first few hours of the TAF before
gradually tapering off this afternoon.

There will be a low (<30% chance) for storms through the
afternoon, especially toward NE MO and west-central IL, before
falling further this evening. Otherwise, VFR conditions should
persist with southerly winds, becoming a bit gusty tomorrow.

BSH

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
356 PM CDT Sat May 16 2026

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-172100-
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-
356 PM CDT Sat May 16 2026

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

.DAYS ONE THROUGH SEVEN...This afternoon through Friday.

More detailed information can be accessed at:
https://www.weather.gov/media/lsx/DssPacket.pdf

The Area Forecast Discussion is available at:
https://forecast.weather.gov/
product.php?issuedby=LSX&product=AFD&site=lsx

.KEY MESSAGES...

- Additional scattered thunderstorms are possible (20-30%) this
  afternoon and evening. The main risk is large hail and damaging
  winds.

- Additional thunderstorm chances return early this week with a
  more widespread severe weather threat possible along a slow
  moving cold front Monday night into Tuesday.

NOTE: Starting May 29, 2026, this outlook product will be
discontinued. Please see the above products for more detailed
forecast information.

WFO LSX