Alert archive / Missouri / Tornado Warnings in 2026

Tornado Warning 18, NWS St. Louis, MO

April 17, 2026Lewis County, Missouri; Adams County, Illinois

NWS St. Louis, MO issued this tornado warning at Apr 17, 2026, 6:23 PM CDT for Lewis County, Missouri; Adams County, Illinois. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 17, 2026, 6:23 PM CDT (23:23 UTC)
Expired
Apr 17, 2026, 7:04 PM CDT
In force
41 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.0 in

Counties Adams County, IL, Lewis County, MO

The radar

The Quad Cities radar (KDVN), 177 km from the middle of the area, began a volume at 23:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Apr 17, 3:31 PM CDTTornado WatchSPC8 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.4 hours before the alert went out and 250 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2026-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 84 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2026-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
84 J/kg
Mixed-layer CIN
-150 J/kg
Mixed-layer LCL
1053 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
164 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

605 
WFUS53 KLSX 172323
TORLSX
ILC001-MOC111-180015-
/O.NEW.KLSX.TO.W.0018.260417T2323Z-260418T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service St Louis MO
623 PM CDT Fri Apr 17 2026

The National Weather Service in St Louis has issued a

* Tornado Warning for...
  Northwestern Adams County in west central Illinois...
  Northern Lewis County in northeastern Missouri...

* Until 715 PM CDT.

* At 623 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 7 miles north of Lewistown, or 16 miles west of Canton,
  moving east at 65 mph.

  HAZARD...Tornado and quarter size hail.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without
           shelter. Mobile homes will be damaged or destroyed. Damage
           to roofs, windows and vehicles will occur. Tree damage is
           likely.

* This tornado will be near...
  Canton around 635 PM CDT.

Other locations impacted by the tornado include Monticello, Meyer,
Lima, Loraine and Woodville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to an interior room on the lowest floor of a well-built building
away from windows. If you are outdoors, in a mobile home, or in a
vehicle, move to the closest substantial shelter and protect yourself
from flying debris.

Heavy rainfall is hiding this tornado. Do not wait to see or hear the
tornado. Take cover now!

&&

LAT...LON 4010 9188 4026 9187 4025 9150 4024 9150
      4024 9151 4023 9150 4022 9150 4021 9151
      4020 9151 4020 9117 4012 9119
TIME...MOT...LOC 2323Z 263DEG 56KT 4018 9182

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Elmore
5 follow-up statements
115 
WWUS53 KLSX 172332
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
632 PM CDT Fri Apr 17 2026

ILC001-MOC111-180015-
/O.CON.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Adams IL-Lewis MO-
632 PM CDT Fri Apr 17 2026

...TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR
NORTHWESTERN ADAMS AND NORTHEASTERN LEWIS COUNTIES...

At 632 PM CDT, a severe thunderstorm capable of producing a tornado
was located 7 miles northwest of Canton, moving east at 65 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows and vehicles will occur. Tree damage is
         likely.

This tornado will be near...
  Canton around 635 PM CDT.

Other locations impacted by the tornado include Meyer, Lima, Loraine
and Woodville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to an interior room on the lowest floor of a well-built building
away from windows. If you are outdoors, in a mobile home, or in a
vehicle, move to the closest substantial shelter and protect yourself
from flying debris.

Heavy rainfall is hiding this tornado. Do not wait to see or hear the
tornado. Take cover now!

&&

LAT...LON 4011 9174 4025 9174 4025 9150 4024 9151
      4023 9150 4021 9151 4020 9151 4020 9117
      4012 9119
TIME...MOT...LOC 2323Z 263DEG 56KT 4018 9181

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Elmore
513 
WWUS53 KLSX 172341 RRA
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
641 PM CDT Fri Apr 17 2026

ILC001-MOC111-180015-
/O.CON.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Adams IL-Lewis MO-
641 PM CDT Fri Apr 17 2026

...TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR
NORTHWESTERN ADAMS AND NORTHEASTERN LEWIS COUNTIES...

At 641 PM CDT, a severe thunderstorm capable of producing a tornado
was located 7 miles northeast of Canton, moving east at 65 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows and vehicles will occur. Tree damage is
         likely.

Other locations impacted by the tornado include Lima, Meyer, Loraine
and Woodville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to an interior room on the lowest floor of a well-built building
away from windows. If you are outdoors, in a mobile home, or in a
vehicle, move to the closest substantial shelter and protect yourself
from flying debris.

Heavy rainfall is hiding this tornado. Do not wait to see or hear the
tornado. Take cover now!

&&

LAT...LON 4011 9167 4025 9159 4025 9150 4024 9151
      4023 9150 4022 9151 4020 9151 4020 9117
      4012 9119
TIME...MOT...LOC 2332Z 263DEG 56KT 4020 9163

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Elmore
366 
WWUS53 KLSX 172349
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
649 PM CDT Fri Apr 17 2026

MOC111-172359-
/O.CAN.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Lewis MO-
649 PM CDT Fri Apr 17 2026

...TORNADO WARNING IS CANCELLED FOR NORTHEASTERN LEWIS COUNTY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. However, gusty winds are
still possible with this thunderstorm.

A Tornado Watch remains in effect until 1100 PM CDT Friday for a
portion of northeast Missouri.

&&

LAT...LON 4011 9147 4020 9139 4020 9117 4012 9119
TIME...MOT...LOC 2341Z 263DEG 56KT 4021 9145

$$


ILC001-180015-
/O.CON.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Adams IL-
649 PM CDT Fri Apr 17 2026

...TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR
NORTHWESTERN ADAMS COUNTY...

At 649 PM CDT, a severe thunderstorm capable of producing a tornado
was located 7 miles north of Mendon, or 15 miles east of Canton,
moving east at 70 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows and vehicles will occur. Tree damage is
         likely.

Other locations impacted by the tornado include Loraine, Lima and
Woodville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to an interior room on the lowest floor of a well-built building
away from windows. If you are outdoors, in a mobile home, or in a
vehicle, move to the closest substantial shelter and protect yourself
from flying debris.

Heavy rainfall is hiding this tornado. Do not wait to see or hear the
tornado. Take cover now!

&&

LAT...LON 4011 9147 4020 9139 4020 9117 4012 9119
TIME...MOT...LOC 2341Z 269DEG 58KT 4019 9143

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Elmore
843 
WWUS53 KLSX 172356
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
656 PM CDT Fri Apr 17 2026

ILC001-180015-
/O.CON.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Adams IL-
656 PM CDT Fri Apr 17 2026

...TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR NORTH
CENTRAL ADAMS COUNTY...

At 656 PM CDT, a severe thunderstorm capable of producing a tornado
was located 8 miles northwest of Golden, or 18 miles north of Quincy
Regional Airport, moving east at 70 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows and vehicles will occur. Tree damage is
         likely.

Other locations impacted by the tornado include Woodville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to an interior room on the lowest floor of a well-built building
away from windows. If you are outdoors, in a mobile home, or in a
vehicle, move to the closest substantial shelter and protect yourself
from flying debris.

Heavy rainfall is hiding this tornado. Do not wait to see or hear the
tornado. Take cover now!

&&

LAT...LON 4012 9135 4020 9128 4020 9117 4012 9119
TIME...MOT...LOC 2349Z 269DEG 58KT 4019 9126

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Elmore
850 
WWUS53 KLSX 180004
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
704 PM CDT Fri Apr 17 2026

ILC001-180014-
/O.CAN.KLSX.TO.W.0018.000000T0000Z-260418T0015Z/
Adams IL-
704 PM CDT Fri Apr 17 2026

...TORNADO WARNING IS CANCELLED FOR NORTH CENTRAL ADAMS COUNTY...

The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled. However, gusty winds are still possible with this
thunderstorm.

A Tornado Watch remains in effect until 1100 PM CDT Friday for a
portion of west central Illinois.

&&

LAT...LON 4012 9135 4020 9128 4020 9117 4012 9119
TIME...MOT...LOC 2356Z 269DEG 58KT 4020 9112

$$

Elmore

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 17, 7:57 AM CDTFlood WatchLSXAudrain, Boone, Callaway, Cole, Knox, Lewis and 9 more19 hr
Apr 17, 3:06 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Callaway39 min
Apr 17, 3:10 PM CDTSevere Thunderstorm WarningLSXLincoln, Saint Charles, Warren50 min
Apr 17, 3:26 PM CDTSevere Thunderstorm WarningLSXSaint Charles, Saint Louis49 min
Apr 17, 3:30 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Shelby45 min
Apr 17, 3:39 PM CDTSevere Thunderstorm WarningLSXLincoln, Pike49 min
Apr 17, 3:40 PM CDTSevere Thunderstorm WarningLSXAudrain, Monroe, Ralls37 min
Apr 17, 3:45 PM CDTSevere Thunderstorm WarningLSXPike32 min
Apr 17, 4:04 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis23 min
Apr 17, 4:11 PM CDTSevere Thunderstorm WarningLSXSaint Charles, Saint Louis25 min
Apr 17, 5:03 PM CDTTornado WarningLSXKnox, Lewis, Shelby42 min
Apr 17, 5:38 PM CDTTornado WarningLSXLewis52 min
Apr 17, 5:51 PM CDTSevere Thunderstorm Warning Considerable damage threatLSXKnox, Shelby54 min
Apr 17, 5:58 PM CDTTornado WarningLSXKnox32 min
Apr 17, 6:13 PM CDTSevere Thunderstorm Warning Considerable damage threatLSXLewis47 min
Apr 17, 6:46 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Marion, Monroe, Ralls, Shelby44 min
Apr 17, 4:22 PM CDTSevere Thunderstorm WarningLSXBrown, Pike38 min
Apr 17, 6:53 PM CDTSevere Thunderstorm Warning Considerable damage threatLSXAdams52 min

Nearby

Tornado Warnings in Missouri, 2026Tornado Warnings in Illinois, 2026Every tornado warning in 2026Tornadoes in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.