Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 88, NWS St. Louis, MO

June 20, 20219 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 20, 2021, 11:29 PM CDT for 9 counties in Missouri. It was in force for 31 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, 11:29 PM CDT (04:29 UTC)
Expired
Jun 21, 2021, 12:00 AM CDT
In force
31 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Boone County, MO, Callaway County, MO, Cole County, MO, Franklin County, MO, Gasconade County, MO, Lincoln County, MO, Montgomery County, MO, Osage County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 87 km from the middle of the area, began a volume at 04:30 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, 11:55 PM CDTTSTM WND DMG3 Wnw Linn, MOA LARGE OLD TREE WAS BLOWN OVER ONTO A HOUSE CAUSING MINOR ROOF DAMAGE.

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, 4.5 hours before the alert went out and 278 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.

691 
WUUS53 KLSX 210429
SVRLSX
MOC019-027-051-071-073-113-139-151-219-210500-
/O.NEW.KLSX.SV.W.0088.210621T0429Z-210621T0500Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
1129 PM CDT Sun Jun 20 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Central Cole County in central Missouri...
  Southeastern Boone County in central Missouri...
  Southwestern Lincoln County in east central Missouri...
  Montgomery County in east central Missouri...
  Callaway County in central Missouri...
  Northwestern Franklin County in east central Missouri...
  Osage County in central Missouri...
  Warren County in east central Missouri...
  Gasconade County in east central Missouri...

* Until midnight CDT.

* At 1129 PM CDT, severe thunderstorms were located along a line
  extending from near Hawk Point to 6 miles east of Hermann to near
  Linn, moving east at 50 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Hawk Point around 1135 PM CDT.
  Troy, New Haven and Treloar around 1140 PM CDT.
  Washington, Marthasville and Innsbrook around 1145 PM CDT.

Other locations in the path of these severe thunderstorms include
Mount Sterling and Drake.

This includes Interstate 70 in Missouri between exits 155 and 200.
 
This also includes Deutschheim Historic Site, Clarks Hill/Norton
Historic Site, Jefferson Landing Historic Site, and Graham Cave State
Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3884 9222 3911 9140 3900 9095 3863 9096
      3833 9160 3857 9245
TIME...MOT...LOC 0429Z 283DEG 45KT 3900 9112 3871 9132 3849 9193 

HAIL...<.75IN
WIND...60MPH
 
$$

19
1 follow-up statement
393 
WWUS53 KLSX 210444
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1144 PM CDT Sun Jun 20 2021

MOC019-210454-
/O.CAN.KLSX.SV.W.0088.000000T0000Z-210621T0500Z/
Boone MO-
1144 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BOONE COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

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

LAT...LON 3880 9202 3906 9121 3900 9095 3863 9096
      3833 9160 3849 9217
TIME...MOT...LOC 0444Z 278DEG 56KT 3875 9096 3869 9106 3842 9188 

$$

MOC027-051-071-073-113-139-151-219-210500-
/O.CON.KLSX.SV.W.0088.000000T0000Z-210621T0500Z/
Cole MO-Lincoln MO-Montgomery MO-Callaway MO-Franklin MO-Osage MO-
Warren MO-Gasconade MO-
1144 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT
FOR EAST CENTRAL COLE...SOUTHWESTERN LINCOLN...CENTRAL MONTGOMERY...
SOUTHEASTERN CALLAWAY...NORTHWESTERN FRANKLIN...OSAGE...WARREN AND
GASCONADE COUNTIES...

At 1144 PM CDT, severe thunderstorms were located along a line
extending from near New Melle to near Marthasville to Rich Fountain,
moving east at 65 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Marthasville, Mount Sterling and Drake.

This also includes Deutschheim Historic Site, Clarks Hill/Norton
Historic Site, and Graham Cave State Park.
 
This includes Interstate 70 in Missouri between exits 170 and 200.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3880 9202 3906 9121 3900 9095 3863 9096
      3833 9160 3849 9217
TIME...MOT...LOC 0444Z 278DEG 56KT 3875 9096 3869 9106 3842 9188 

HAIL...<.75IN
WIND...60MPH
 
$$

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, 10:42 PM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Moniteau48 min
Jun 20, 10:55 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Callaway, Montgomery35 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.