Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 163, NWS St. Louis, MO

August 31, 20214 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 31, 2021, 9:49 PM CDT for 4 counties in Missouri. It was in force for 41 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
Aug 31, 2021, 9:49 PM CDT (02:49 UTC)
Expired
Aug 31, 2021, 10:30 PM CDT
In force
41 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Iron County, MO, Madison County, MO, Reynolds County, MO, Saint Francois County, MO

The radar

The St Louis radar (KLSX), 128 km from the middle of the area, began a volume at 02:49 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

Springfield, MO (KSGF), launched 00:00Z, 2.8 hours before the alert went out and 298 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 208 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.1939Sfc1 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
208 J/kg
Mixed-layer CIN
-108 J/kg
Mixed-layer LCL
1625 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

567 
WUUS53 KLSX 010249
SVRLSX
MOC093-123-179-187-010330-
/O.NEW.KLSX.SV.W.0163.210901T0249Z-210901T0330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
949 PM CDT Tue Aug 31 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Iron County in southeastern Missouri...
  Northeastern Reynolds County in southeastern Missouri...
  Madison County in southeastern Missouri...
  Southwestern St. Francois County in southeastern Missouri...

* Until 1030 PM CDT.

* At 948 PM CDT, severe thunderstorms were located along a line
  extending from near Farmington to near Knob Lick to 9 miles east of
  Oates, moving southeast at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Farmington, Desloge, Fredericktown, Ironton, Park Hills, Pilot
  Knob, Iron Mountain Lake, Arcadia, Annapolis, Junction City,
  Cobalt, Marquand, Knob Lick, Buckhorn, Glover, Roselle, Saco,
  Leadington, Des Arc and Granite.

This also includes Johnsons Shut-Ins State Park, Fort Davidson
Historic Site, Elephant Rocks State Park, and Taum Sauk Mountain
State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3762 9099 3772 9050 3793 9050 3789 9045
      3788 9046 3761 9015 3755 9014 3731 9014
      3732 9055 3727 9055 3727 9074 3724 9074
TIME...MOT...LOC 0248Z 318DEG 25KT 3783 9044 3767 9044 3756 9087 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Byrd
2 follow-up statements
760 
WWUS53 KLSX 010313
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1013 PM CDT Tue Aug 31 2021

MOC187-010322-
/O.CAN.KLSX.SV.W.0163.000000T0000Z-210901T0330Z/
St. Francois MO-
1013 PM CDT Tue Aug 31 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN ST. FRANCOIS
COUNTY IS CANCELLED...

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

LAT...LON 3754 9094 3764 9024 3764 9019 3761 9015
      3755 9014 3731 9014 3732 9055 3727 9055
      3727 9074 3724 9074
TIME...MOT...LOC 0312Z 330DEG 23KT 3756 9025 3752 9040 3744 9073 

$$

MOC093-123-179-010330-
/O.CON.KLSX.SV.W.0163.000000T0000Z-210901T0330Z/
Iron MO-Reynolds MO-Madison MO-
1013 PM CDT Tue Aug 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 PM CDT
FOR SOUTHEASTERN IRON...NORTHEASTERN REYNOLDS AND MADISON COUNTIES IN
SOUTHEASTERN MISSOURI...

At 1012 PM CDT, severe thunderstorms were located along a line
extending from near Cobalt to 6 miles southwest of Fredericktown to
near Glover, moving southeast at 25 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Fredericktown, Arcadia, Annapolis, Junction City, Cobalt, Marquand,
Buckhorn, Glover, Saco, Des Arc, Catherine Place, Hogan, Vulcan,
Black, Sabula, Mine La Motte, Chloride and Lesterville.

This also includes Taum Sauk Mountain State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3754 9094 3764 9024 3764 9019 3761 9015
      3755 9014 3731 9014 3732 9055 3727 9055
      3727 9074 3724 9074
TIME...MOT...LOC 0312Z 330DEG 23KT 3756 9025 3752 9040 3744 9073 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Byrd
344 
WWUS53 KLSX 010330
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1030 PM CDT Tue Aug 31 2021

MOC093-123-179-010340-
/O.EXP.KLSX.SV.W.0163.000000T0000Z-210901T0330Z/
Iron MO-Reynolds MO-Madison MO-
1030 PM CDT Tue Aug 31 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN IRON...
NORTHEASTERN REYNOLDS AND MADISON COUNTIES IN SOUTHEASTERN MISSOURI
HAS EXPIRED...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning has
been allowed to expire.  However gusty winds and heavy rain are still
possible with these thunderstorms.

LAT...LON 3754 9094 3764 9024 3764 9019 3761 9015
      3755 9014 3731 9014 3732 9055 3727 9055
      3727 9074 3724 9074
TIME...MOT...LOC 0330Z 318DEG 25KT 3747 9015 3743 9030 3735 9063 

$$

Byrd

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 9:03 PM CDTSevere Thunderstorm WarningLSXSaint Francois, Washington42 min
Aug 31, 9:31 PM CDTSevere Thunderstorm WarningLSXSaint Francois, Washington44 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.