Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 1, NWS St. Louis, MO

March 11, 20214 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Mar 11, 2021, 12:43 PM CST for 4 counties in Missouri. It was in force for 22 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
Mar 11, 2021, 12:43 PM CST (18:43 UTC)
Expired
Mar 11, 2021, 1:05 PM CST
In force
22 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, Saint Francois County, MO, Sainte Genevieve County, MO

The radar

The St Louis radar (KLSX), 113 km from the middle of the area, began a volume at 18:42 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 6.7 hours before the alert went out and 313 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, Lincoln, IL at 12:00Z on 2021-03-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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, Lincoln, IL at 12:00Z on 2021-03-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 114 square meters per square second.1939587897117136Sfc1 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
2 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
500 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
114 m²/s²
0-3 km storm-relative helicity
198 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

026 
WUUS53 KLSX 111843
SVRLSX
MOC093-123-186-187-111930-
/O.NEW.KLSX.SV.W.0001.210311T1843Z-210311T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
1243 PM CST Thu Mar 11 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northeastern Iron County in southeastern Missouri...
  Southern Ste. Genevieve County in southeastern Missouri...
  Northern Madison County in southeastern Missouri...
  Southern St. Francois County in southeastern Missouri...

* Until 130 PM CST.

* At 1242 PM CST, a severe thunderstorm was located over Iron
  Mountain, moving east at 40 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Farmington, Fredericktown, Bismarck, Ironton, Park Hills, Pilot
  Knob, Iron Mountain Lake, Womac, Knob Lick, Iron Mountain, Coffman,
  Roselle, Granite, Minnith, Mine La Motte, Libertyville, Doe Run and
  River Aux Vases.

This includes Interstate 55 in Missouri near exit 143.
 
This also includes Hawn State Park, Fort Davidson Historic Site, and
Elephant Rocks State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3761 9072 3774 9077 3773 9065 3777 9064
      3789 9003 3780 9001 3768 9011 3764 9015
      3758 9015
TIME...MOT...LOC 1842Z 259DEG 35KT 3767 9065 

TORNADO...POSSIBLE
HAIL...0.75IN
WIND...60MPH
 
$$

Carney
2 follow-up statements
662 
WWUS53 KLSX 111856
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1256 PM CST Thu Mar 11 2021

MOC093-111906-
/O.CAN.KLSX.SV.W.0001.000000T0000Z-210311T1930Z/
Iron MO-
1256 PM CST Thu Mar 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN IRON COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3760 9053 3764 9054 3765 9065 3773 9065
      3777 9064 3789 9003 3780 9001 3768 9011
      3764 9015 3758 9015
TIME...MOT...LOC 1856Z 257DEG 29KT 3769 9052 

$$

MOC123-186-187-111930-
/O.CON.KLSX.SV.W.0001.000000T0000Z-210311T1930Z/
Ste. Genevieve MO-Madison MO-St. Francois MO-
1256 PM CST Thu Mar 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM CST
FOR SOUTHERN STE. GENEVIEVE...NORTHERN MADISON AND SOUTHERN ST.
FRANCOIS COUNTIES IN SOUTHEASTERN MISSOURI...

At 1256 PM CST, a severe thunderstorm was located near Iron Mountain
Lake, moving east at 35 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Farmington, Fredericktown, Bismarck, Park Hills, Iron Mountain Lake,
Womac, Knob Lick, Iron Mountain, Coffman, Minnith, Mine La Motte,
Libertyville, Doe Run and River Aux Vases.

This also includes Hawn State Park.
 
This includes Interstate 55 in Missouri near exit 143.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3760 9053 3764 9054 3765 9065 3773 9065
      3777 9064 3789 9003 3780 9001 3768 9011
      3764 9015 3758 9015
TIME...MOT...LOC 1856Z 257DEG 29KT 3769 9052 

TORNADO...POSSIBLE
HAIL...0.75IN
WIND...60MPH
 
$$

Carney
499 
WWUS53 KLSX 111905
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
105 PM CST Thu Mar 11 2021

MOC123-186-187-111915-
/O.CAN.KLSX.SV.W.0001.000000T0000Z-210311T1930Z/
Ste. Genevieve MO-Madison MO-St. Francois MO-
105 PM CST Thu Mar 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN STE. GENEVIEVE...
NORTHERN MADISON AND SOUTHERN ST. FRANCOIS COUNTIES IN SOUTHEASTERN
MISSOURI IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

LAT...LON 3760 9053 3764 9054 3765 9065 3773 9065
      3777 9064 3789 9003 3780 9001 3768 9011
      3764 9015 3758 9015
TIME...MOT...LOC 1904Z 259DEG 35KT 3771 9040 

$$

Carney

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 11, 3:27 AM CSTFlood WatchLSXBoone, Callaway, Cole, Crawford, Franklin, Gasconade and 14 more55 hr
Mar 11, 1:58 PM CSTSevere Thunderstorm WarningLSXIron, Madison, Sainte Genevieve, Saint Francois47 min
Mar 11, 3:38 PM CSTAreal Flood AdvisoryLSXCrawford, Iron, Sainte Genevieve, Saint Francois, Washington3 hr

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.