Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 82, NWS St. Louis, MO

June 20, 2021Audrain County, Boone County, Monroe County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jun 20, 2021, 9:42 PM CDT for Audrain County, Boone County, Monroe County, Missouri. It was in force for 48 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 20, 2021, 9:42 PM CDT (02:42 UTC)
Expired: Jun 20, 2021, 10:30 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 Audrain County, MO, Boone County, MO, Monroe County, MO

The radar

The St Louis radar (KLSX), 148 km from the middle of the area, began a volume at 02:42 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

Time	Report	Where	Remark
Jun 20, 10:23 PM CDT	TSTM WND DMG	Sturgeon, MO	DOWNED TREE BLOCKING ROADWAY.
Jun 20, 10:23 PM CDT	TSTM WND DMG	Sturgeon, MO	TREE DOWN BLOCKING ROADWAY.

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.

Issued	Product	Office	Lasted
Jun 20, 8:10 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 2.7 hours before the alert went out and 296 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2316 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 2228 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 8.8

Open this sounding in Storm Lab

The text

As transmitted.

606 
WUUS53 KLSX 210242
SVRLSX
MOC007-019-137-210330-
/O.NEW.KLSX.SV.W.0082.210621T0242Z-210621T0330Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northeastern Boone County in central Missouri...
  Western Audrain County in central Missouri...
  Southern Monroe County in northeastern Missouri...

* Until 1030 PM CDT.

* At 942 PM CDT, severe thunderstorms were located along a line
  extending from near Paris to near Higbee, moving southeast at 45
  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...
  Sturgeon around 1000 PM CDT.

Other locations in the path of these severe thunderstorms include
Santa Fe, Hallsville and Centralia.

This also includes Union Covered Bridge Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3925 9243 3925 9231 3944 9231 3949 9230
      3938 9172 3906 9197 3906 9211 3918 9247
TIME...MOT...LOC 0242Z 296DEG 39KT 3944 9210 3926 9256 

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

19

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 8:41 PM CDT	Severe Thunderstorm Warning	LSX	Knox, Lewis, Shelby	49 min
Jun 20, 9:07 PM CDT	Tornado Warning	LSX	Marion, Shelby	38 min
Jun 20, 9:17 PM CDT	Severe Thunderstorm Warning	LSX	Knox, Lewis, Marion, Monroe, Ralls, Shelby	43 min
Jun 20, 9:59 PM CDT	Severe Thunderstorm Warning	LSX	Marion, Monroe, Pike, Ralls	46 min
Jun 20, 10:10 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Boone, Monroe, Montgomery, Pike, Ralls	50 min
Jun 20, 10:22 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Boone, Callaway	38 min
Jun 20, 10:27 PM CDT	Areal Flood Advisory	LSX	Audrain, Boone, Monroe	3 hr
Jun 20, 10:42 PM CDT	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Moniteau	48 min
Jun 20, 10:55 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Boone, Callaway, Montgomery	35 min
Jun 20, 11:29 PM CDT	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Franklin, Gasconade, Lincoln and 3 more	31 min
Jun 20, 11:41 PM CDT	Severe Thunderstorm Warning	LSX	Lincoln, Saint Charles	19 min
Jun 20, 11:59 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade, Montgomery, Osage, Warren	31 min
Jun 21, 12:34 AM CDT	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Moniteau	26 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2021 Every 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.