Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 145, NWS St. Louis, MO

August 12, 2021Calhoun County, Greene County, Pike County, Illinois; 5 counties in Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 12, 2021, 5:27 PM CDT for Calhoun County, Greene County, Pike County, Illinois; 5 counties in Missouri. It was in force for 48 min. 3 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, 5:27 PM CDT (22:27 UTC)
Expired
Aug 12, 2021, 6:15 PM CDT
In force
48 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Calhoun County, IL, Greene County, IL, Pike County, IL, Audrain County, MO, Lincoln County, MO, Montgomery County, MO, Pike County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 81 km from the middle of the area, began a volume at 22:30 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
Aug 12, 5:48 PM CDTTSTM WND DMG3 Nne Moscow Mills, MOAT LEAST THREE POWER POLES SNAPPED ALONG HWY 47.
Aug 12, 5:48 PM CDTTSTM WND DMGTroy, MONUMEROUS TREES, TREE LIMBS AND POWER LINES BLOWN DOWN ACROSS THE NORTHERN HALF OF THE COUNTY. A LARGE TREE BRANCH WAS BLOWN ONTO A HOUSE. ALSO, A TRAMPOLINE AS BLOWN INTO THE SIDE OF A HOUSE BREAKING A WINDOW.
Aug 12, 5:48 PM CDTTSTM WND DMGTroy, MONUMEROUS TREES, TREE LIMBS AND POWER LINES BLOWN DOWN ACROSS THE NORTHERN HALF OF THE COUNTY. A LARGE TREE BRANCH WAS BLOWN ONTO A HOUSE. ALSO, A TRAMPOLINE WAS BLOWN INTO THE SIDE OF A HOUSE BREAKING A WINDOW.

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
Aug 12, 5:19 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.5 hours before the alert went out and 224 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1191 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 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
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.

004 
WUUS53 KLSX 122227
SVRLSX
ILC013-061-149-MOC007-113-139-163-219-122315-
/O.NEW.KLSX.SV.W.0145.210812T2227Z-210812T2315Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northwestern Calhoun County in southwestern Illinois...
  Northwestern Greene County in southwestern Illinois...
  Southern Pike County in west central Illinois...
  Lincoln County in east central Missouri...
  East central Audrain County in central Missouri...
  Northern Montgomery County in east central Missouri...
  Northeastern Warren County in east central Missouri...
  Pike County in northeastern Missouri...

* Until 615 PM CDT.

* At 526 PM CDT, severe thunderstorms were located along a line
  extending from near Louisiana to near New Hartford to near
  Wellsville, moving east at 35 mph.

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

  SOURCE...This line of storms has a history of wind damage. 

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

* Severe thunderstorms will be near...
  Bowling Green and New Hartford around 530 PM CDT.
  Louisiana around 535 PM CDT.
  Atlas and Pike around 540 PM CDT.
  Bellflower around 545 PM CDT.

Other locations in the path of these severe thunderstorms include
Clarksville, Pleasant Hill, Eolia, Hawk Point, Belleview and Davis.

This also includes Cuivre River State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3948 9043 3912 9066 3885 9100 3901 9163
      3927 9138 3960 9120 3960 9118 3961 9119
      3972 9113
TIME...MOT...LOC 2226Z 285DEG 30KT 3949 9115 3926 9130 3910 9151 

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

$$

Elmore
3 follow-up statements
372 
WWUS53 KLSX 122243
SVSLSX

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

MOC007-122252-
/O.CAN.KLSX.SV.W.0145.000000T0000Z-210812T2315Z/
Audrain MO-
543 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL AUDRAIN COUNTY 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 east central Missouri.

LAT...LON 3948 9043 3912 9066 3885 9100 3899 9153
      3924 9128 3956 9109 3970 9107
TIME...MOT...LOC 2242Z 270DEG 30KT 3946 9100 3923 9115 3907 9136 

$$

ILC013-061-149-MOC113-139-163-219-122315-
/O.CON.KLSX.SV.W.0145.000000T0000Z-210812T2315Z/
Calhoun IL-Greene IL-Pike IL-Lincoln MO-Montgomery MO-Warren MO-
Pike MO-
543 PM CDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM CDT
FOR NORTHWESTERN CALHOUN AND NORTHWESTERN GREENE COUNTIES IN
SOUTHWESTERN ILLINOIS...SOUTHEASTERN PIKE COUNTY IN WEST CENTRAL
ILLINOIS...LINCOLN...NORTHEASTERN MONTGOMERY...NORTHEASTERN WARREN
COUNTIES IN EAST CENTRAL MISSOURI AND EASTERN PIKE COUNTIES IN
NORTHEASTERN MISSOURI...

At 542 PM CDT, severe thunderstorms were located along a line
extending from Pike to 7 miles east of New Hartford to near
Bellflower, moving east at 35 mph.

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

SOURCE...This storm has a history of wind damage. 

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

Locations impacted include...
  Louisiana, Atlas, Clarksville, Pike, Pleasant Hill, Eolia, Hawk 
  Point, Belleview, Elsberry, Davis, Troy, Moscow Mills, Hardin and 
  Fountain N' Lakes.

This also includes Cuivre River State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3948 9043 3912 9066 3885 9100 3899 9153
      3924 9128 3956 9109 3970 9107
TIME...MOT...LOC 2242Z 270DEG 30KT 3946 9100 3923 9115 3907 9136 

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

$$

Elmore
136 
WWUS53 KLSX 122255
SVSLSX

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

MOC139-122304-
/O.CAN.KLSX.SV.W.0145.000000T0000Z-210812T2315Z/
Montgomery MO-
555 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN MONTGOMERY COUNTY
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 east central Missouri.

LAT...LON 3912 9066 3885 9100 3891 9123 3929 9099
      3948 9088 3938 9049
TIME...MOT...LOC 2254Z 285DEG 30KT 3944 9090 3921 9105 3905 9126 

$$

ILC013-061-149-MOC113-163-219-122315-
/O.CON.KLSX.SV.W.0145.000000T0000Z-210812T2315Z/
Calhoun IL-Greene IL-Pike IL-Lincoln MO-Warren MO-Pike MO-
555 PM CDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM CDT
FOR NORTHWESTERN CALHOUN AND WEST CENTRAL GREENE COUNTIES IN
SOUTHWESTERN ILLINOIS...SOUTH CENTRAL PIKE COUNTY IN WEST CENTRAL
ILLINOIS...LINCOLN...NORTHEASTERN WARREN COUNTIES IN EAST CENTRAL
MISSOURI AND SOUTHEASTERN PIKE COUNTIES IN NORTHEASTERN MISSOURI...

At 554 PM CDT, severe thunderstorms were located along a line
extending from Pleasant Hill to near Eolia to near Bellflower, moving
east at 35 mph.

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

SOURCE...This line of storms has a history of wind damage.

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

Locations impacted include...
Troy, Elsberry, Moscow Mills, Davis, Hardin, Pleasant Hill, Hawk
Point, Eolia, Clarksville, Fountain N' Lakes, Belleview, Nebo,
Kampsville, Eldred, Silex, Hamburg, Paynesville, Whiteside, Annada
and Cave.

This also includes Cuivre River State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3912 9066 3885 9100 3891 9123 3929 9099
      3948 9088 3938 9049
TIME...MOT...LOC 2254Z 285DEG 30KT 3944 9090 3921 9105 3905 9126 

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

$$

Elmore
254 
WWUS53 KLSX 122313
SVSLSX

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

ILC013-061-149-MOC113-163-219-122323-
/O.EXP.KLSX.SV.W.0145.000000T0000Z-210812T2315Z/
Calhoun IL-Greene IL-Pike IL-Lincoln MO-Warren MO-Pike MO-
613 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CALHOUN AND WEST
CENTRAL GREENE COUNTIES IN SOUTHWESTERN ILLINOIS...SOUTH CENTRAL PIKE
COUNTY IN WEST CENTRAL ILLINOIS...LINCOLN...NORTHEASTERN WARREN
COUNTIES IN EAST CENTRAL MISSOURI AND SOUTHEASTERN PIKE COUNTIES IN
NORTHEASTERN MISSOURI WILL EXPIRE AT 615 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
southwestern Illinois...and east central Missouri.

LAT...LON 3912 9066 3885 9100 3891 9123 3929 9099
      3948 9088 3938 9049
TIME...MOT...LOC 2313Z 270DEG 30KT 3940 9072 3917 9087 3901 9108 

$$

Elmore

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 4:45 PM CDTSevere Thunderstorm WarningLSXAdams, Pike45 min
Aug 12, 4:50 PM CDTSevere Thunderstorm WarningLSXPike40 min
Aug 12, 4:56 PM CDTAreal Flood AdvisoryLSXAdams4 hr
Aug 12, 5:28 PM CDTAreal Flood AdvisoryLSXBond, Madison4 hr
Aug 12, 5:51 PM CDTSevere Thunderstorm WarningLSXCalhoun54 min
Aug 12, 6:37 PM CDTSevere Thunderstorm WarningLSXClinton, Madison, Monroe, Saint Clair, Washington53 min
Aug 12, 3:58 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Monroe, Shelby62 min
Aug 12, 6:41 PM CDTAreal Flood AdvisoryLSXLincoln, Saint Charles, Saint Louis4 hr

Nearby

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