Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 81, NWS St. Louis, MO

June 20, 2021Adams County, Illinois; 6 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 20, 2021, 9:17 PM CDT for Adams County, Illinois; 6 counties in Missouri. It was in force for 43 min. 7 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jun 20, 2021, 9:17 PM CDT (02:17 UTC)
Expired
Jun 20, 2021, 10:00 PM CDT
In force
43 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
70.0 mph

Counties Adams County, IL, Knox County, MO, Lewis County, MO, Marion County, MO, Monroe County, MO, Ralls County, MO, Shelby County, MO

The radar

The St Louis radar (KLSX), 153 km from the middle of the area, began a volume at 02:18 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.

What was reported inside it

TimeReportWhereRemark
Jun 20, 9:20 PM CDTTSTM WND DMG2 S Shelbyville, MOTREES DOWN OVER HIGHWAY 15 SOUTH OF SHELBYVILLE.
Jun 20, 9:20 PM CDTTSTM WND DMG3 Sw Shelbina, MOMAJOR ROOF DAMAGE TO A BARN ON THE NORTH SIDE OF HIGHWAY WW NEAR INTERSECTION WITH SHELBY CO. ROAD 425.
Jun 20, 9:20 PM CDTTSTM WND DMG4 Ene Maud, MOA BARN ROOF WAS TORN OFF AND THE BARN DOOR WAS BLOWN A QUARTER OF A MILE TO THE SOUTH (INTO MONROE COUNTY). ALSO, AN EMPTY SEMI TRAILER WAS BLOWN OVER ON TOP OF A PICKUP TRUCK. THE HOUSE LOST A NUMBER OF SHINGLES.
Jun 20, 9:24 PM CDTTSTM WND DMGLewistown, MOSIX INCH DIAMETER TREE LIMBS DOWNED. TIME ESTIMATED FROM RADAR.
Jun 20, 9:44 PM CDTTSTM WND DMGMonroe City, MOSEMI TRUCK WAS BLOWN OVER AND MOVED 20 FEET AT BUSINESS ON THE WEST SIDE OF TOWN.
Jun 20, 9:44 PM CDTTSTM WND DMGMonroe City, MOTREES DOWN IN MONROE CITY.
Jun 20, 10:10 PM CDTTSTM WND DMGPerry, MOSEVERAL LARGE TREE LIMBS WERE BLOWN DOWN AROUND TOWN.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Jun 20, 8:10 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.3 hours before the alert went out and 231 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, Davenport, at 00:00Z on 2021-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1058 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, Davenport, at 00:00Z on 2021-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 174 square meters per square second.19395878Sfc1 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
1058 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
1009 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
230 m²/s²
Significant tornado parameter
1.4
Supercell composite
7.8

Open this sounding in Storm Lab

The text

As transmitted.

571 
WUUS53 KLSX 210217
SVRLSX
ILC001-MOC103-111-127-137-173-205-210300-
/O.NEW.KLSX.SV.W.0081.210621T0217Z-210621T0300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
917 PM CDT Sun Jun 20 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southwestern Adams County in west central Illinois...
  Southeastern Knox County in northeastern Missouri...
  Western Ralls County in northeastern Missouri...
  Marion County in northeastern Missouri...
  Shelby County in northeastern Missouri...
  Southern Lewis County in northeastern Missouri...
  Monroe County in northeastern Missouri...

* Until 1000 PM CDT.

* At 917 PM CDT, severe thunderstorms were located along a line
  extending from near Ewing to near Paris, moving east at 50 mph.

  HAZARD...70 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect considerable 
           tree damage. Wind damage is also likely to mobile homes, 
           roofs, and outbuildings.

* Severe thunderstorms will be near...
  Lewistown and Ewing around 920 PM CDT.
  Maywood around 930 PM CDT.
  La Grange around 935 PM CDT.

Other locations in the path of these severe thunderstorms include
Quincy, Perry and Center.

This includes Interstate 172 between exits 10 and 19.
 
This also includes Wakonda State Park and Mark Twain Lake
Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4006 9121 3935 9162 3948 9231 3962 9230
      4013 9198
TIME...MOT...LOC 0217Z 275DEG 42KT 4002 9179 3950 9208 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...70MPH
 
$$

19
2 follow-up statements
533 
WWUS53 KLSX 210235
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
935 PM CDT Sun Jun 20 2021

ILC001-MOC103-111-210244-
/O.CAN.KLSX.SV.W.0081.000000T0000Z-210621T0300Z/
Adams IL-Knox MO-Lewis MO-
935 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN ADAMS...
SOUTHEASTERN KNOX AND SOUTHERN LEWIS COUNTIES IS CANCELLED...

The storms which prompted the warning have weakened. Therefore, the 
warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 100 AM CDT for
west central Illinois...and northeastern Missouri.

LAT...LON 3995 9198 3985 9144 3980 9137 3935 9162
      3948 9231 3962 9230 3995 9209
TIME...MOT...LOC 0234Z 284DEG 25KT 3969 9169 3947 9218 

$$

MOC127-137-173-205-210300-
/O.CON.KLSX.SV.W.0081.000000T0000Z-210621T0300Z/
Ralls MO-Marion MO-Shelby MO-Monroe MO-
935 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT
FOR WESTERN RALLS...MARION...SHELBY AND MONROE COUNTIES...

At 934 PM CDT, severe thunderstorms were located along a line
extending from near Monroe City to Madison, moving east at 30 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
  Monroe City, Rensselaer, Spaulding and Hannibal.

This also includes Mark Twain Lake Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3995 9198 3985 9144 3980 9137 3935 9162
      3948 9231 3962 9230 3995 9209
TIME...MOT...LOC 0234Z 284DEG 25KT 3969 9169 3947 9218 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...70MPH
 
$$

19
795 
WWUS53 KLSX 210247
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
947 PM CDT Sun Jun 20 2021

MOC127-137-173-205-210300-
/O.CON.KLSX.SV.W.0081.000000T0000Z-210621T0300Z/
Ralls MO-Marion MO-Shelby MO-Monroe MO-
947 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT
FOR WESTERN RALLS...MARION...SOUTHEASTERN SHELBY AND MONROE
COUNTIES...

At 946 PM CDT, severe thunderstorms were located along a line
extending from Rensselaer to Paris, moving east at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Hannibal, Palmyra, Monroe City, Shelbina, Paris, Warren, Perry,
Madison, Center, Rensselaer, Spaulding, Maud, Woodlawn, Granville,
Philadelphia, Hunnewell, Holliday, Stoutsville, The Landing and
Florida.

This also includes Mark Twain Lake Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3985 9144 3980 9137 3935 9162 3948 9231
      3961 9229 3974 9195 3989 9168
TIME...MOT...LOC 0246Z 275DEG 42KT 3968 9152 3946 9201 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...70MPH
 
$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 9:59 PM CDTSevere Thunderstorm WarningLSXPike46 min
Jun 20, 8:41 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Shelby49 min
Jun 20, 9:07 PM CDTTornado WarningLSXMarion, Shelby38 min
Jun 20, 9:42 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Monroe48 min
Jun 20, 10:10 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Monroe, Montgomery, Pike, Ralls50 min
Jun 20, 10:22 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Callaway38 min
Jun 20, 10:27 PM CDTAreal Flood AdvisoryLSXAudrain, Boone, Monroe3 hr
Jun 20, 10:42 PM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Moniteau48 min
Jun 20, 10:55 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Callaway, Montgomery35 min
Jun 20, 11:29 PM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Franklin, Gasconade, Lincoln and 3 more31 min
Jun 20, 11:41 PM CDTSevere Thunderstorm WarningLSXLincoln, Saint Charles19 min
Jun 20, 11:59 PM CDTSevere Thunderstorm WarningLSXFranklin, Gasconade, Montgomery, Osage, Warren31 min
Jun 21, 12:34 AM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Moniteau26 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2021Severe Thunderstorm Warnings in Illinois, 2021Every severe thunderstorm warning in 2021

Sources

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