Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 166, NWS St. Louis, MO

September 20, 2021Audrain County, Monroe County, Ralls County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Sep 20, 2021, 9:56 PM CDT for Audrain County, Monroe County, Ralls County, Missouri. It was in force for 51 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
Sep 20, 2021, 9:56 PM CDT (02:56 UTC)
Expired
Sep 20, 2021, 10:47 PM CDT
In force
51 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Audrain County, MO, Monroe County, MO, Ralls County, MO

The radar

The St Louis radar (KLSX), 135 km from the middle of the area, began a volume at 02:58 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.9 hours before the alert went out and 270 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, Davenport, at 00:00Z on 2021-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1090 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, Davenport, at 00:00Z on 2021-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 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
1090 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
1240 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.7

Open this sounding in Storm Lab

The text

As transmitted.

878 
WUUS53 KLSX 210256
SVRLSX
MOC007-137-173-210400-
/O.NEW.KLSX.SV.W.0166.210921T0256Z-210921T0400Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
956 PM CDT Mon Sep 20 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southwestern Ralls County in northeastern Missouri...
  Northern Audrain County in central Missouri...
  Monroe County in northeastern Missouri...

* Until 1100 PM CDT.

* At 956 PM CDT, severe thunderstorms were located along a line
  extending from near Madison to 10 miles south of Paris to near
  Centralia, moving east at 50 mph.

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

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Paris and Santa Fe around 1010 PM CDT.

Other locations in the path of these severe thunderstorms include
Perry, Farber, Vandalia and Center.

This also includes Union Covered Bridge Historic Site and Mark Twain
Lake Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3966 9197 3966 9172 3950 9147 3926 9143
      3923 9210 3924 9213 3931 9216 3944 9230
TIME...MOT...LOC 0256Z 251DEG 43KT 3941 9218 3934 9207 3924 9206 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Britt
3 follow-up statements
217 
WWUS53 KLSX 210312
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1012 PM CDT Mon Sep 20 2021

MOC007-137-173-210400-
/O.CON.KLSX.SV.W.0166.000000T0000Z-210921T0400Z/
Ralls MO-Audrain MO-Monroe MO-
1012 PM CDT Mon Sep 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT
FOR SOUTHWESTERN RALLS...NORTHEASTERN AUDRAIN AND MONROE COUNTIES...

At 1012 PM CDT, severe thunderstorms were located along a line
extending from near Paris to near Santa Fe, moving east at 50 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
  Perry, Farber, Monroe City, Vandalia and Center.

This also includes Union Covered Bridge Historic Site and Mark Twain
Lake Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3966 9197 3966 9172 3950 9147 3926 9143
      3923 9210 3934 9209 3947 9216
TIME...MOT...LOC 0312Z 248DEG 45KT 3949 9196 3942 9185 3932 9184 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Britt
371 
WWUS53 KLSX 210327
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1027 PM CDT Mon Sep 20 2021

MOC007-137-173-210400-
/O.CON.KLSX.SV.W.0166.000000T0000Z-210921T0400Z/
Ralls MO-Audrain MO-Monroe MO-
1027 PM CDT Mon Sep 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT
FOR SOUTHWESTERN RALLS...NORTHEASTERN AUDRAIN AND EASTERN MONROE
COUNTIES...

At 1027 PM CDT, severe thunderstorms were located along a line
extending from 6 miles south of Monroe City to near Perry to 7 miles
north of Farber, moving east at 45 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Vandalia, Monroe City, Santa Fe, Perry, Center, Farber, Stoutsville,
The Landing, Florida and Indian Creek.

This also includes Mark Twain Lake Recreational Area.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3966 9197 3966 9172 3950 9147 3926 9143
      3924 9189 3935 9189 3946 9194
TIME...MOT...LOC 0327Z 249DEG 41KT 3956 9173 3948 9164 3938 9159 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Britt
425 
WWUS53 KLSX 210347
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1047 PM CDT Mon Sep 20 2021

MOC007-137-173-210356-
/O.CAN.KLSX.SV.W.0166.000000T0000Z-210921T0400Z/
Ralls MO-Audrain MO-Monroe MO-
1047 PM CDT Mon Sep 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN RALLS...
NORTHEASTERN AUDRAIN AND EASTERN MONROE COUNTIES IS CANCELLED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled.

LAT...LON 3966 9197 3966 9172 3950 9147 3926 9143
      3924 9189 3935 9189 3946 9194
TIME...MOT...LOC 0344Z 251DEG 43KT 3963 9148 3955 9139 3945 9134 

$$

Britt

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 8:45 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis45 min
Sep 20, 10:35 PM CDTSevere Thunderstorm WarningLSXMarion, Pike, Ralls40 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.