Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 86, NWS St. Louis, MO

June 20, 20214 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 20, 2021, 10:42 PM CDT for 4 counties in Missouri. It was in force for 48 min. 1 report 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, 10:42 PM CDT (03:42 UTC)
Expired
Jun 20, 2021, 11:30 PM CDT
In force
48 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
70.0 mph

Counties Boone County, MO, Callaway County, MO, Cole County, MO, Moniteau County, MO

The radar

The St Louis radar (KLSX), 122 km from the middle of the area, began a volume at 03:45 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, 11:04 PM CDTTSTM WND GST 583 Ne Ashland, MO58 MPH MEASURED GUST AT COLUMBIA AIRPORT.

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

Springfield, MO (KSGF), launched 00:00Z, 3.7 hours before the alert went out and 245 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, Springfield, MO at 00:00Z on 2021-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1346 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, Springfield, MO at 00:00Z on 2021-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
1346 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
1683 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
264 m²/s²
Significant tornado parameter
0.2
Supercell composite
5.8

Open this sounding in Storm Lab

The text

As transmitted.

190 
WUUS53 KLSX 210342
SVRLSX
MOC019-027-051-135-210430-
/O.NEW.KLSX.SV.W.0086.210621T0342Z-210621T0430Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
1042 PM CDT Sun Jun 20 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northern Cole County in central Missouri...
  Southern Boone County in central Missouri...
  Southwestern Callaway County in central Missouri...
  Northeastern Moniteau County in central Missouri...

* Until 1130 PM CDT.

* At 1041 PM CDT, severe thunderstorms were located along a line
  extending from near Columbia to near Tipton, moving east at 55 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...
  Easley around 1045 PM CDT.
  Ashland and Columbia Regional Airport around 1050 PM CDT.
  Jamestown around 1055 PM CDT.
  Centertown around 1100 PM CDT.

Other locations in the path of these severe thunderstorms include St.
Martins, Jefferson City, Holts Summit, Lake Mykee Town, New
Bloomfield and Lake Mykee.

This also includes Clarks Hill/Norton Historic Site and Jefferson
Landing Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3868 9262 3892 9250 3873 9180 3867 9185
      3866 9188 3862 9191 3859 9195 3858 9199
      3857 9201 3856 9200 3855 9202 3853 9203
      3851 9202
TIME...MOT...LOC 0341Z 279DEG 50KT 3890 9239 3872 9274 

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

19
1 follow-up statement
379 
WWUS53 KLSX 210413
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1113 PM CDT Sun Jun 20 2021

MOC019-027-051-135-210430-
/O.CON.KLSX.SV.W.0086.000000T0000Z-210621T0430Z/
Cole MO-Boone MO-Callaway MO-Moniteau MO-
1113 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT
FOR NORTHERN COLE...SOUTHERN BOONE...SOUTHWESTERN CALLAWAY AND
NORTHEASTERN MONITEAU COUNTIES...

At 1111 PM CDT, severe thunderstorms were located along a line
extending from near Fulton to near St. Martins, moving east at 60
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...
  Lake Mykee Town and Lake Mykee.

This also includes Clarks Hill/Norton Historic Site and Jefferson
Landing Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3868 9262 3892 9250 3873 9180 3867 9185
      3866 9188 3862 9191 3859 9195 3858 9199
      3857 9201 3856 9200 3855 9202 3853 9203
      3851 9202
TIME...MOT...LOC 0411Z 284DEG 53KT 3878 9192 3860 9227 

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, 8:41 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Shelby49 min
Jun 20, 9:07 PM CDTTornado WarningLSXMarion, Shelby38 min
Jun 20, 9:17 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Marion, Monroe, Ralls, Shelby43 min
Jun 20, 9:42 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Monroe48 min
Jun 20, 9:59 PM CDTSevere Thunderstorm WarningLSXMarion, Monroe, Pike, Ralls46 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, 10:55 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, 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.