Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 25, NWS St. Louis, MO

April 7, 20214 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 7, 2021, 5:37 PM CDT for 4 counties in Missouri. It was in force for 68 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
Apr 7, 2021, 5:37 PM CDT (22:37 UTC)
Expired
Apr 7, 2021, 6:45 PM CDT
In force
68 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
60.0 mph

Counties Franklin County, MO, Jefferson County, MO, Saint Francois County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 47 km from the middle of the area, began a volume at 22:40 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
Apr 7, 5:58 PM CDTTSTM WND GST 601 Ne Old Mines, MOESTIMATED 50 TO 60 MPH WIND GUSTS.
Apr 7, 6:12 PM CDTTSTM WND DMGHillsboro, MOLARGE TREE LIMB SNAPPED, APPROXIMATELY 6 TO 8 IN DIAMETER, ESTIMATED WITH PHOTO.

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
Apr 7, 12:02 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.6 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, Lincoln, IL at 12:00Z on 2021-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 56 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 2021-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 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
56 J/kg
Mixed-layer CIN
-173 J/kg
Mixed-layer LCL
1001 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

867 
WUUS53 KLSX 072237
SVRLSX
MOC071-099-187-221-072345-
/O.NEW.KLSX.SV.W.0025.210407T2237Z-210407T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
537 PM CDT Wed Apr 7 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Jefferson County in east central Missouri...
  Washington County in east central Missouri...
  Southeastern Franklin County in east central Missouri...
  Northwestern St. Francois County in southeastern Missouri...

* Until 645 PM CDT.

* At 536 PM CDT, a severe thunderstorm was located near Anthonies
  Mill, moving northeast at 50 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Arnold, Festus, Union, Pacific, Bonne Terre, De Soto, Pevely,
  Desloge, Crystal City, St. Clair, Herculaneum, Hillsboro, Byrnes
  Mill, Potosi, Bismarck, Leadwood, High Ridge, Murphy, Anthonies
  Mill and Antonia.

This includes the following highways...
 Interstate 44 in Missouri between exits 239 and 247, and near exit
257.
 Interstate 55 in Missouri between exits 170 and 191.

This also includes Washington State Park, St. Francois State Park,
Mastodon Historic Site, Sandy Creek Covered Bridge Historic Site,
Gov. Dunklin's Grave Historic Site, and Robertsville State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3774 9109 3838 9109 3850 9077 3850 9074
      3848 9073 3845 9067 3849 9065 3847 9062
      3850 9059 3850 9041 3848 9042 3845 9041
      3845 9034 3834 9037 3824 9036 3812 9025
      3809 9033 3804 9041 3773 9064
TIME...MOT...LOC 2236Z 221DEG 41KT 3799 9105 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

BSH
5 follow-up statements
479 
WWUS53 KLSX 072258
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
558 PM CDT Wed Apr 7 2021

MOC071-099-187-221-072345-
/O.CON.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Jefferson MO-Washington MO-Franklin MO-St. Francois MO-
558 PM CDT Wed Apr 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR JEFFERSON...EASTERN WASHINGTON...SOUTHEASTERN FRANKLIN AND
NORTHWESTERN ST. FRANCOIS COUNTIES...

At 558 PM CDT, a severe thunderstorm was located near Old Mines,
moving northeast at 50 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Arnold, Festus, Pacific, Bonne Terre, De Soto, Pevely, Desloge,
Crystal City, Herculaneum, Hillsboro, Byrnes Mill, Potosi, Bismarck,
Leadwood, High Ridge, Murphy, Antonia, Barnhart, Cedar Hill and Gray
Summit.

This also includes Washington State Park, St. Francois State Park,
Mastodon Historic Site, Sandy Creek Covered Bridge Historic Site,
Gov. Dunklin's Grave Historic Site, and Robertsville State Park.
 
This includes the following highways...
 Interstate 44 in Missouri exit 247 and near exit 257.
 Interstate 55 in Missouri between exits 170 and 191.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3774 9084 3844 9093 3850 9077 3850 9074
      3848 9073 3845 9067 3849 9065 3847 9062
      3850 9059 3850 9041 3848 9042 3845 9041
      3845 9034 3834 9037 3824 9036 3812 9025
      3809 9033 3804 9041 3773 9064
TIME...MOT...LOC 2258Z 228DEG 43KT 3809 9073 

TORNADO...POSSIBLE
HAIL...0.88IN
WIND...60MPH
 
$$

BSH
483 
WWUS53 KLSX 072305
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
605 PM CDT Wed Apr 7 2021

MOC071-221-072315-
/O.CAN.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Washington MO-Franklin MO-
605 PM CDT Wed Apr 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN WASHINGTON AND
SOUTHEASTERN FRANKLIN COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
southeastern and east central Missouri.

LAT...LON 3808 9064 3808 9066 3810 9065 3809 9068
      3810 9068 3820 9078 3847 9074 3845 9067
      3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041 3773 9065
TIME...MOT...LOC 2305Z 221DEG 41KT 3815 9066 

$$

MOC099-187-072345-
/O.CON.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Jefferson MO-St. Francois MO-
605 PM CDT Wed Apr 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR JEFFERSON AND NORTHWESTERN ST. FRANCOIS COUNTIES...

At 605 PM CDT, a severe thunderstorm was located near De Soto, moving
northeast at 45 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Arnold, Festus, Bonne Terre, De Soto, Pevely, Crystal City,
Herculaneum, Hillsboro, Byrnes Mill, Bismarck, Leadwood, High Ridge,
Barnhart, Cedar Hill, Murphy, Antonia, Oakville, Olympian Village,
Cedar Hill Lakes and House Springs.

This also includes St. Francois State Park, Mastodon Historic Site,
Sandy Creek Covered Bridge Historic Site, and Gov. Dunklin's Grave
Historic Site.
 
This includes Interstate 55 in Missouri between exits 170 and 191.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3808 9064 3808 9066 3810 9065 3809 9068
      3810 9068 3820 9078 3847 9074 3845 9067
      3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041 3773 9065
TIME...MOT...LOC 2305Z 221DEG 41KT 3815 9066 

TORNADO...POSSIBLE
HAIL...0.88IN
WIND...60MPH
 
$$

BSH
200 
WWUS53 KLSX 072315
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
615 PM CDT Wed Apr 7 2021

MOC187-072324-
/O.CAN.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
St. Francois MO-
615 PM CDT Wed Apr 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN ST. FRANCOIS
COUNTY IS CANCELLED...
    
The severe thunderstorm which prompted the warning has weakened. 
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
southeastern and east central Missouri.

LAT...LON 3801 9062 3807 9061 3808 9066 3810 9065
      3809 9068 3820 9078 3847 9074 3845 9067
      3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041 3800 9058
TIME...MOT...LOC 2314Z 221DEG 41KT 3823 9057 

$$

MOC099-072345-
/O.CON.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Jefferson MO-
615 PM CDT Wed Apr 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR JEFFERSON COUNTY...

At 614 PM CDT, a severe thunderstorm was located over Hillsboro,
moving northeast at 45 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Arnold, Festus, De Soto, Pevely, Crystal City, Herculaneum,
Hillsboro, Byrnes Mill, High Ridge, Barnhart, Cedar Hill, Murphy,
Antonia, Oakville, Olympian Village, Cedar Hill Lakes, House Springs,
Dittmer, Horine and Imperial.

This also includes Mastodon Historic Site, Sandy Creek Covered Bridge
Historic Site, and Gov. Dunklin's Grave Historic Site.
 
This includes Interstate 55 in Missouri between exits 170 and 191.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3801 9062 3807 9061 3808 9066 3810 9065
      3809 9068 3820 9078 3847 9074 3845 9067
      3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041 3800 9058
TIME...MOT...LOC 2314Z 221DEG 41KT 3823 9057 

TORNADO...POSSIBLE
HAIL...0.88IN
WIND...60MPH
 
$$

BSH
957 
WWUS53 KLSX 072328
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
628 PM CDT Wed Apr 7 2021

MOC099-072345-
/O.CON.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Jefferson MO-
628 PM CDT Wed Apr 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR CENTRAL JEFFERSON COUNTY...

At 627 PM CDT, a severe thunderstorm was located over Antonia, moving
northeast at 45 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Arnold, Festus, Pevely, Crystal City, Herculaneum, Byrnes Mill, High
Ridge, Barnhart, Murphy, Antonia, Oakville, Olympian Village, House
Springs, Horine, Imperial, Scotsdale, Parkdale, Kimmswick, Hematite
and Otto.

This also includes Mastodon Historic Site, Sandy Creek Covered Bridge
Historic Site, and Gov. Dunklin's Grave Historic Site.
 
This includes Interstate 55 in Missouri between exits 170 and 191.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041
TIME...MOT...LOC 2327Z 221DEG 41KT 3835 9044 

TORNADO...POSSIBLE
HAIL...0.88IN
WIND...60MPH
 
$$

BSH
190 
WWUS53 KLSX 072337
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
637 PM CDT Wed Apr 7 2021

MOC099-072346-
/O.EXP.KLSX.SV.W.0025.000000T0000Z-210407T2345Z/
Jefferson MO-
637 PM CDT Wed Apr 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL JEFFERSON COUNTY WILL
EXPIRE AT 645 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
southeastern and east central Missouri.

LAT...LON 3849 9065 3847 9062 3850 9059 3850 9041
      3848 9042 3845 9041 3845 9034 3830 9037
      3822 9036 3812 9025 3804 9041
TIME...MOT...LOC 2336Z 221DEG 41KT 3841 9038 

$$

BSH

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 7, 3:06 PM CDTSevere Thunderstorm WarningLSXMoniteau39 min
Apr 7, 4:04 PM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Moniteau, Osage26 min
Apr 7, 4:27 PM CDTAreal Flood AdvisoryLSXBoone, Cole, Moniteau3 hr
Apr 7, 5:09 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Marion, Monroe, Ralls, Shelby19 min
Apr 7, 6:27 PM CDTSevere Thunderstorm WarningLSXSaint Louis, City of Saint Louis49 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.