Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 147, NWS St. Louis, MO

August 12, 20215 counties in Missouri; 5 counties in Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 12, 2021, 6:37 PM CDT for 5 counties in Missouri; 5 counties in Illinois. It was in force for 53 min. 28 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: Aug 12, 2021, 6:37 PM CDT (23:37 UTC)
Expired: Aug 12, 2021, 7:30 PM CDT
In force: 53 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Clinton County, IL, Madison County, IL, Monroe County, IL, Saint Clair County, IL, Washington County, IL, City of Saint Louis, MO, Franklin County, MO, Jefferson County, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 59 km from the middle of the area, began a volume at 23:37 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
Aug 12, 6:37 PM CDT	TSTM WND DMG	1 N Kirkwood, MO	SEVERAL TREES AND NUMEROUS TREE LIMBS WERE BLOWN DOWN NEAR THE INTERSECTION OF MANCHESTER ROAD AND GEYER ROAD.
Aug 12, 6:37 PM CDT	TSTM WND DMG	Kirkwood, MO	SEVERAL TREES AND NUMEROUS TREE LIMBS BLOWN DOWN NEAR THE INTERSECTION OF MANCHESTER ROAD AND GEYER ROAD.
Aug 12, 6:39 PM CDT	TSTM WND GST 58	1 Wnw Berkeley, MO	CORRECTS PREVIOUS TSTM WND GST REPORT FROM 1 WNW BERKELEY. WIND GUST REPORTED AT ST. LOUIS-LAMBERT INTERNATIONAL AIRPORT.
Aug 12, 6:41 PM CDT	TSTM WND DMG	1 Sse Webster Groves, MO	TREE DOWN BLOCKING WATSON ROAD.
Aug 12, 6:41 PM CDT	TSTM WND DMG	Brentwood, MO	LARGE TREE SNAPPED IN HALF CAUSING DAMAGE TO A HOUSE ON PINE AVENUE NEAR THE INTERSECTION WITH ST. CLAIR IN BRENTWOOD.
Aug 12, 6:41 PM CDT	TSTM WND DMG	Murphy, MO	POWER LINES DOWN AND MULTIPLE TREES SNAPPED.
Aug 12, 6:42 PM CDT	TSTM WND DMG	1 Nw Shrewsbury, MO	LARGE TREE LIMB BLOWN DOWN.
Aug 12, 6:42 PM CDT	TSTM WND GST 58	1 Wnw Berkeley, MO	WIND GUST REPORTED AT ST. LOUIS-LAMBERT INTERNATIONAL AIRPORT.
Aug 12, 6:44 PM CDT	TSTM WND DMG	1 Ne Maplewood, MO	SEVERAL TREES DOWN ACROSS MCCAUSLAND AVE.
Aug 12, 6:51 PM CDT	TSTM WND DMG	Oakville, MO	NUMEROUS TREE LIMBS BLOWN DOWN.
Aug 12, 6:54 PM CDT	TSTM WND DMG	Granite City, IL	LARGE TREE BLOWN OVER ONTO ILLINOIS ROUTE 3.
Aug 12, 6:54 PM CDT	TSTM WND DMG	Normandy, MO	LIMBS DOWN
Aug 12, 6:54 PM CDT	TSTM WND DMG	Normandy, MO	LIMBS DOWN.
Aug 12, 6:55 PM CDT	TSTM WND DMG	Barnhart, MO	NUMEROUS TREE LIMBS BLOWN DOWN. VIA FACEBOOK.
Aug 12, 6:55 PM CDT	TSTM WND GST 58	1 Ssw Hazelwood, MO
Aug 12, 6:58 PM CDT	TSTM WND DMG	3 N Lemay, MO	1 TO 3 INCH LIMBS DOWN.
Aug 12, 6:58 PM CDT	TSTM WND DMG	3 Nne Lemay, MO	1 TO 3 INCH TREE LIMBS DOWN
Aug 12, 7:00 PM CDT	TSTM WND DMG	2 Sw Pevely, MO	LARGE TREE DOWN ACROSS ROAD
Aug 12, 7:00 PM CDT	TSTM WND DMG	2 Sw Pevely, MO	LARGE TREE DOWN ACROSS ROAD.
Aug 12, 7:00 PM CDT	TSTM WND DMG	Oakville, MO	LARGE TREE LIMBS DOWN.
Aug 12, 7:01 PM CDT	TSTM WND GST 67	1 Ese Sauget, IL
Aug 12, 7:01 PM CDT	TSTM WND GST 67	1 Ne Cahokia, IL
Aug 12, 7:05 PM CDT	TSTM WND DMG	Herculaneum, MO	NUMEROUS TREE LIMBS BLOWN DOWN. WINDS ESTIMATED BETWEEN 60 AND 70 MPH.
Aug 12, 7:07 PM CDT	TSTM WND DMG	1 Ssw Collinsville, IL	SEVERAL TREES BLOWN DOWN AROUND TOWN. ALSO, SEVERAL POWER LINES WERE BLOWN DOWN.
Aug 12, 7:10 PM CDT	TSTM WND DMG	2 Sse Belleville, IL	VIA TWITTER PHOTO OF SMALL TREE UPROOTED AND MEDIUM SIZED TREE LIMB SNAPPED.
Aug 12, 7:10 PM CDT	TSTM WND DMG	Millstadt, IL	NUMEROUS TREE LIMBS BLOWN DOWN. VIA FACEBOOK.
Aug 12, 7:20 PM CDT	TSTM WND DMG	3 Nnw Freeburg, IL	POWER LINES BLOWN DOWN AT THE INTERSECTION OF ILLINOIS ROUTE 15 AND JEFFERSON ROAD.
Aug 12, 7:22 PM CDT	TSTM WND DMG	Freeburg, IL	NUMEROUS TREES AND TREE LIMBS BLOWN DOWN AROUND TOWN.

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
Aug 12, 5:19 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.6 hours before the alert went out and 249 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: 1191 J/kg
Mixed-layer CIN: -177 J/kg
Mixed-layer LCL: 1149 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 140 m²/s²
0-3 km storm-relative helicity: 128 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.1

Open this sounding in Storm Lab

The text

As transmitted.

264 
WUUS53 KLSX 122337
SVRLSX
ILC027-119-133-163-189-MOC071-099-183-189-510-130030-
/O.NEW.KLSX.SV.W.0147.210812T2337Z-210813T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
637 PM CDT Thu Aug 12 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southwestern Clinton County in south central Illinois...
  Monroe County in southwestern Illinois...
  Southern Madison County in southwestern Illinois...
  Western Washington County in south central Illinois...
  St. Clair County in southwestern Illinois...
  St. Louis City in east central Missouri...
  Northeastern St. Charles County in east central Missouri...
  Jefferson County in east central Missouri...
  Southeastern Franklin County in east central Missouri...
  St. Louis County in east central Missouri...

* Until 730 PM CDT.

* At 636 PM CDT, severe thunderstorms were located along a line
  extending from East Alton to near Valley Park to near St. Clair,
  moving southeast at 40 mph.

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

  SOURCE...This line of storms has a history of damaging wind gusts.

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

* Severe thunderstorms will be near...
  St. Louis, Kirkwood, Sunset Hills, Des Peres, Valley Park, Fenton, 
  Byrnes Mill, Oakland, Murphy and High Ridge around 640 PM CDT.
  Granite City, Crestwood, Madison, Affton, South Roxana, Grantwood 
  Village, Sappington and Concord around 645 PM CDT.
  Edwardsville, Arnold, Pontoon Beach, Lakeshire, Mehlville, 
  Antonia, Green Park and St. George around 650 PM CDT.
  Collinsville, Maryville, Oakville, Barnhart, Imperial and Dittmer 
  around 655 PM CDT.

Other locations in the path of these severe thunderstorms include
Glen Carbon, Troy, Columbia, Caseyville, Cedar Hill Lakes, Fountain,
O'Fallon, Valmeyer, Waterloo, Hillsboro, St. Jacob, De Soto, Lebanon
and Scott AFB.

This includes the following highways...
 Interstate 64 in Illinois between exits 9 and 41.
 Interstate 44 in Missouri between exits 239 and 247, and between
exits 257 and 277.
 Interstate 55 in Missouri between exits 170 and 191.

This also includes Scott Joplin Historic Site, Route 66 State Park,
Castlewood State Park, Confluence State Park, Mastodon Historic Site,
Sandy Creek Covered Bridge Historic Site, Gov. Dunklin's Grave
Historic Site, Robertsville State Park, and Horseshoe Lake State
Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3855 8929 3822 8967 3822 9003 3813 9004
      3809 9020 3813 9025 3804 9041 3801 9057
      3820 9078 3820 9086 3838 9110 3857 9058
      3890 9025
TIME...MOT...LOC 2336Z 307DEG 34KT 3887 9013 3853 9051 3837 9095 

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

$$

Elmore

2 follow-up statements

662 
WWUS53 KLSX 130005
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
705 PM CDT Thu Aug 12 2021

MOC071-183-130014-
/O.CAN.KLSX.SV.W.0147.000000T0000Z-210813T0030Z/
St. Charles MO-Franklin MO-
705 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ST. CHARLES AND
SOUTHEASTERN FRANKLIN COUNTIES IS CANCELLED...

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

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southwestern Illinois...and southeastern and east central Missouri.

LAT...LON 3855 8929 3822 8967 3822 9003 3813 9004
      3809 9020 3813 9025 3804 9041 3801 9057
      3806 9062 3807 9061 3808 9064 3820 9078
      3837 9074 3851 9045 3883 9014 3881 9012
      3885 9011
TIME...MOT...LOC 0004Z 270DEG 34KT 3873 8985 3839 9023 3823 9067 

$$

ILC027-119-133-163-189-MOC099-189-510-130030-
/O.CON.KLSX.SV.W.0147.000000T0000Z-210813T0030Z/
Clinton IL-Monroe IL-Madison IL-Washington IL-St. Clair IL-
St. Louis City MO-Jefferson MO-St. Louis MO-
705 PM CDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR SOUTHWESTERN CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...MONROE
AND SOUTHERN MADISON COUNTIES IN SOUTHWESTERN ILLINOIS...WESTERN
WASHINGTON COUNTY IN SOUTH CENTRAL ILLINOIS...ST. CLAIR COUNTY IN
SOUTHWESTERN ILLINOIS...JEFFERSON AND SOUTHEASTERN ST. LOUIS COUNTIES
IN EAST CENTRAL MISSOURI AND ST. LOUIS CITY...

At 704 PM CDT, severe thunderstorms were located along a line
extending from near Troy to near Fountain to near Hillsboro, moving
east at 40 mph.

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...This storm has a history of producing damaging wind gusts.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
  Glen Carbon, Troy, Waterloo, St. Jacob, Millstadt, Trenton, 
  Olympian Village, Festus, Pevely, Smithton, Aviston, Horine, 
  Crystal City, Breese, Freeburg, Herculaneum, New Athens, Valmeyer, 
  Mascoutah, New Design and New Memphis.

This also includes Scott Joplin Historic Site, Mastodon Historic
Site, Sandy Creek Covered Bridge Historic Site, Gov. Dunklin's Grave
Historic Site, and Horseshoe Lake State Park.
 
This includes the following highways...
 Interstate 64 in Illinois between exits 9 and 41.
 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 3855 8929 3822 8967 3822 9003 3813 9004
      3809 9020 3813 9025 3804 9041 3801 9057
      3806 9062 3807 9061 3808 9064 3820 9078
      3837 9074 3851 9045 3883 9014 3881 9012
      3885 9011
TIME...MOT...LOC 0004Z 270DEG 34KT 3873 8985 3839 9023 3823 9067 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Elmore

372 
WWUS53 KLSX 130027
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
727 PM CDT Thu Aug 12 2021

ILC027-119-133-163-189-MOC099-189-510-130037-
/O.EXP.KLSX.SV.W.0147.000000T0000Z-210813T0030Z/
Clinton IL-Monroe IL-Madison IL-Washington IL-St. Clair IL-
St. Louis City MO-Jefferson MO-St. Louis MO-
727 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN CLINTON COUNTY IN
SOUTH CENTRAL ILLINOIS...MONROE AND SOUTHERN MADISON COUNTIES IN
SOUTHWESTERN ILLINOIS...WESTERN WASHINGTON COUNTY IN SOUTH CENTRAL
ILLINOIS...ST. CLAIR COUNTY IN SOUTHWESTERN ILLINOIS...JEFFERSON AND
SOUTHEASTERN ST. LOUIS COUNTIES IN EAST CENTRAL MISSOURI AND ST.
LOUIS CITY WILL EXPIRE AT 730 PM CDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
south central and southwestern Illinois...and southeastern and east
central Missouri.

LAT...LON 3855 8929 3822 8967 3822 9003 3813 9004
      3809 9020 3813 9025 3804 9041 3801 9057
      3806 9062 3807 9061 3808 9064 3820 9078
      3837 9074 3851 9045 3883 9014 3881 9012
      3885 9011
TIME...MOT...LOC 0027Z 307DEG 34KT 3861 8966 3827 9004 3811 9048 

$$

Elmore

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 3:58 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Boone, Monroe, Shelby	62 min
Aug 12, 4:45 PM CDT	Severe Thunderstorm Warning	LSX	Marion, Pike, Ralls	45 min
Aug 12, 4:50 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Callaway, Lincoln, Monroe, Montgomery, Pike and 1 more	40 min
Aug 12, 4:56 PM CDT	Areal Flood Advisory	LSX	Lewis, Marion	4 hr
Aug 12, 5:27 PM CDT	Severe Thunderstorm Warning	LSX	Audrain, Lincoln, Montgomery, Pike, Warren	48 min
Aug 12, 5:51 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade, Jefferson, Lincoln, Saint Charles, Saint Louis and 1 more	54 min
Aug 12, 6:41 PM CDT	Areal Flood Advisory	LSX	Lincoln, Saint Charles, Saint Louis	4 hr
Aug 12, 5:28 PM CDT	Areal Flood Advisory	LSX	Bond, Madison	4 hr

Nearby

Severe Thunderstorm Warnings in Missouri, 2021 Severe Thunderstorm Warnings in Illinois, 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.