Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 78, NWS St. Louis, MO

June 19, 2021Franklin County, Saint Charles County, Saint Louis County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 19, 2021, 8:00 PM CDT for Franklin County, Saint Charles County, Saint Louis County, Missouri. It was in force for 21 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
Jun 19, 2021, 8:00 PM CDT (01:00 UTC)
Expired
Jun 19, 2021, 8:21 PM CDT
In force
21 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Franklin County, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 15 km from the middle of the area, began a volume at 01:03 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
Jun 19, 2:43 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.0 hours before the alert went out and 234 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.

284 
WUUS53 KLSX 200100
SVRLSX
MOC071-183-189-200145-
/O.NEW.KLSX.SV.W.0078.210620T0100Z-210620T0145Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  St. Charles County in east central Missouri...
  East central Franklin County in east central Missouri...
  St. Louis County in east central Missouri...

* Until 845 PM CDT.

* At 759 PM CDT, a severe thunderstorm was located over St. Paul,
  moving southeast at 30 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will be near...
  O'Fallon around 810 PM CDT.
  Cottleville around 815 PM CDT.

Other locations in the path of this severe thunderstorm include St.
Charles, St. Peters, Weldon Spring, Harvester, Maryland Heights,
Orchard Farms, Chesterfield, Town and Country, Champ, Florissant,
Hazelwood, Bridgeton, Lambert-St. Louis International Airport,
University City, Ferguson, Creve Coeur, Overland, Clayton, Jennings,
St. Ann, Bellefontaine Neighbors, Berkeley and Richmond Heights.

This includes the following highways...
 Interstate 44 in Missouri between exits 257 and 269.
 Interstate 70 in Missouri between exits 216 and 231.

This also includes Babler Memorial State Park, Route 66 State Park,
Castlewood State Park, and First Missouri State Capitol Historic
Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a DANGEROUS SITUATION. This storm is producing widespread 
wind damage across St Charles County. 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 3881 9012 3878 9016 3877 9018 3859 9040
      3850 9057 3850 9059 3847 9062 3849 9065
      3845 9066 3845 9067 3847 9070 3848 9073
      3847 9074 3858 9094 3871 9096 3888 9059
      3887 9054 3892 9049 3895 9043 3882 9011
TIME...MOT...LOC 0059Z 293DEG 25KT 3886 9073 

HAIL...0.88IN
WIND...60MPH
 
$$

GKS
1 follow-up statement
801 
WWUS53 KLSX 200121
SVSLSX

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

MOC071-183-189-200129-
/O.CAN.KLSX.SV.W.0078.000000T0000Z-210620T0145Z/
St. Charles MO-Franklin MO-St. Louis MO-
821 PM CDT Sat Jun 19 2021

...THE SEVERE THUNDERSTORM WARNING FOR ST. CHARLES...EAST CENTRAL
FRANKLIN AND ST. LOUIS COUNTIES IS CANCELLED...
                
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 cancelled.  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 3881 9012 3878 9016 3877 9018 3859 9040
      3850 9057 3850 9059 3847 9062 3849 9065
      3845 9066 3845 9067 3847 9070 3848 9073
      3847 9074 3858 9094 3871 9096 3888 9059
      3887 9054 3892 9049 3895 9043 3882 9011
TIME...MOT...LOC 0117Z 293DEG 25KT 3880 9056 

$$

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 WarningLSXLincoln, Pike48 min
Jun 19, 7:31 PM CDTSevere Thunderstorm WarningLSXLincoln, Saint Charles44 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, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.