Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 77, NWS St. Louis, MO

June 19, 2021Calhoun County, Illinois; Lincoln County, Saint Charles County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 19, 2021, 7:31 PM CDT for Calhoun County, Illinois; Lincoln County, Saint Charles County, Missouri. It was in force for 44 min. 2 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 19, 2021, 7:31 PM CDT (00:31 UTC)
Expired
Jun 19, 2021, 8:15 PM CDT
In force
44 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Calhoun County, IL, Lincoln County, MO, Saint Charles County, MO

The radar

The St Louis radar (KLSX), 23 km from the middle of the area, began a volume at 00:34 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 19, 7:40 PM CDTTSTM WND DMGFlint Hill, MOCALLER REPORTED TREES DOWN IN HER BACKYARD, UP TO 12IN DIAMETER.
Jun 19, 7:43 PM CDTTSTM WND DMG2 Wnw Lake Saint Louis, MOCALLER REPORTED STREET SIGNS AND LAMP POST DOWN ACROSS THE ROAD, ALMOST HITTING HER CAR.

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 19, 2:43 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.5 hours before the alert went out and 227 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 00:00Z on 2021-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2088 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 00:00Z on 2021-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
2088 J/kg
Mixed-layer CIN
-51 J/kg
Mixed-layer LCL
1087 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
133 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.7

Open this sounding in Storm Lab

The text

As transmitted.

713 
WUUS53 KLSX 200031
SVRLSX
ILC013-MOC113-183-200115-
/O.NEW.KLSX.SV.W.0077.210620T0031Z-210620T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
731 PM CDT Sat Jun 19 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southeastern Calhoun County in southwestern Illinois...
  St. Charles County in east central Missouri...
  Southeastern Lincoln County in east central Missouri...

* Until 815 PM CDT.

* At 731 PM CDT, a severe thunderstorm was located over Fountain N'
  Lakes, moving southeast 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.

* This severe thunderstorm will be near...
  Winfield and Chain of Rocks around 740 PM CDT.
  Lake St. Louis, St. Paul and Josephville around 750 PM CDT.

Other locations in the path of this severe thunderstorm include
O'Fallon, Dardenne Prairie, Cottleville, St. Charles, St. Peters,
Weldon Spring, Harvester and Orchard Farms.

This includes Interstate 70 in Missouri between exits 203 and 227.
 
This also includes Cuivre River State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3902 9058 3897 9055 3896 9053 3896 9050
      3885 9037 3883 9042 3883 9044 3881 9046
      3857 9093 3880 9096 3887 9096 3887 9101
      3895 9111 3904 9093 3911 9076
TIME...MOT...LOC 0031Z 300DEG 26KT 3895 9087 

HAIL...1.00IN
WIND...60MPH
 
$$

GKS
2 follow-up statements
271 
WWUS53 KLSX 200049
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
749 PM CDT Sat Jun 19 2021

ILC013-MOC113-183-200115-
/O.CON.KLSX.SV.W.0077.000000T0000Z-210620T0115Z/
Calhoun IL-St. Charles MO-Lincoln MO-
749 PM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM CDT
FOR SOUTHEASTERN CALHOUN...ST. CHARLES AND SOUTHEASTERN LINCOLN
COUNTIES...

At 746 PM CDT, a severe thunderstorm was located near St. Paul, 
moving southeast at 30 mph.  Trees were blown down due to damaging 
winds in Flint Hill and Lake St Louis. 

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

SOURCE...Trained weather spotters.

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...
  O'Fallon, Dardenne Prairie, Cottleville, St. Charles, St. Peters, 
  Weldon Spring, Harvester and Orchard Farms.

This also includes Cuivre River State Park.
 
This includes Interstate 70 in Missouri between exits 203 and 227.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a DANGEROUS SITUATION. This storm is producing widespread 
wind damage across Flint Hill and Lake St Louis. SEEK SHELTER NOW 
inside a sturdy structure and stay away from windows.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3902 9058 3897 9055 3896 9053 3896 9050
      3885 9037 3883 9042 3883 9044 3881 9046
      3857 9093 3880 9096 3887 9096 3887 9101
      3895 9111 3904 9093 3911 9076
TIME...MOT...LOC 0046Z 300DEG 26KT 3889 9075 

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

GKS
952 
WWUS53 KLSX 200116
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
816 PM CDT Sat Jun 19 2021

ILC013-MOC113-183-200125-
/O.EXP.KLSX.SV.W.0077.000000T0000Z-210620T0115Z/
Calhoun IL-St. Charles MO-Lincoln MO-
816 PM CDT Sat Jun 19 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CALHOUN...ST.
CHARLES AND SOUTHEASTERN LINCOLN COUNTIES HAS EXPIRED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.  However small
hail, gusty winds and heavy rain are still possible with this
thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southwestern Illinois...and east central Missouri.

LAT...LON 3902 9058 3897 9055 3896 9053 3896 9050
      3885 9037 3883 9042 3883 9044 3881 9046
      3857 9093 3880 9096 3887 9096 3887 9101
      3895 9111 3904 9093 3911 9076
TIME...MOT...LOC 0115Z 300DEG 26KT 3878 9052 

$$

GKS

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 7:12 PM CDTSevere Thunderstorm WarningLSXCalhoun48 min
Jun 19, 8:00 PM CDTSevere Thunderstorm WarningLSXFranklin, Saint Charles, Saint Louis21 min
Jun 19, 8:42 PM CDTFlash Flood WarningLSXAudrain, Boone, Monroe6 hr
Jun 19, 9:33 PM CDTSevere Thunderstorm WarningLSXCallaway42 min
Jun 19, 11:49 PM CDTAreal Flood WarningLSXMarion, Pike, Ralls11 hr
Jun 20, 1:39 AM CDTFlash Flood WarningLSXBoone5 hr
Jun 20, 2:13 AM CDTAreal Flood WarningLSXAudrain, Boone, Monroe3 hr

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.