Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 143, NWS St. Louis, MO

August 12, 2021Marion County, Pike County, Ralls County, Missouri; Adams County, Pike County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 12, 2021, 4:45 PM CDT for Marion County, Pike County, Ralls County, Missouri; Adams County, Pike County, Illinois. It was in force for 45 min. 8 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, 4:45 PM CDT (21:45 UTC)
Expired: Aug 12, 2021, 5:30 PM CDT
In force: 45 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Adams County, IL, Pike County, IL, Marion County, MO, Pike County, MO, Ralls County, MO

The radar

The St Louis radar (KLSX), 129 km from the middle of the area, began a volume at 21:45 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, 4:45 PM CDT	TSTM WND DMG	1 Nnw Hannibal, MO	LARGE PORTION OF FLAT METAL ROOF REMOVED FROM HANNIBAL-LAGRANGE UNIVERSITY BUILDING, ALONG WITH SOME TREES BLOWN OVER AND BROKEN TREE LIMBS.
Aug 12, 4:45 PM CDT	TSTM WND DMG	1 Nnw Hannibal, MO	LARGE TREE LAID ONTO A VEHICLE.
Aug 12, 4:45 PM CDT	TSTM WND DMG	1 Nw Hannibal, MO	WIND DAMAGE TO A HARDWARE STORE.
Aug 12, 4:45 PM CDT	TSTM WND DMG	4 Nw Hannibal, MO	TREE DOWN ONTO A CAMPER.
Aug 12, 4:50 PM CDT	TSTM WND DMG	1 Nne Hannibal, MO	TREES DOWN.
Aug 12, 4:55 PM CDT	TSTM WND DMG	4 Nnw Hannibal, MO	CAMPER FLIPPED OVER.
Aug 12, 4:55 PM CDT	TSTM WND GST 51	4 Wnw Hannibal, MO	MEASURED KHAE AWOS.
Aug 12, 5:01 PM CDT	TSTM WND GST 52	4 Ne Burton, IL	MEASURED KUIN ASOS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 221 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2463 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

205 
WUUS53 KLSX 122145
SVRLSX
ILC001-149-MOC127-163-173-122230-
/O.NEW.KLSX.SV.W.0143.210812T2145Z-210812T2230Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Central Pike County in west central Illinois...
  Southern Adams County in west central Illinois...
  Northern Ralls County in northeastern Missouri...
  Southern Marion County in northeastern Missouri...
  Northwestern Pike County in northeastern Missouri...

* Until 530 PM CDT.

* At 444 PM CDT, severe thunderstorms were located along a line
  extending from near Quincy Regional Airport to near Hannibal to
  near Warren, moving southeast at 25 mph.

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

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Hannibal and Quincy Regional Airport around 450 PM CDT.
  Payson and Fall Creek around 455 PM CDT.

Other locations in the path of these severe thunderstorms include
Rensselaer, Beverly, Spaulding, Barry, New London and Center.

This includes the following highways...
 Interstate 172 between exits 2 and 14.
 Interstate 72 between exits 4 and 31.

This also includes Siloam Springs State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3990 9092 3984 9092 3984 9070 3952 9093
      3951 9152 3961 9172 3966 9172 3966 9181
      3968 9185 3974 9185 3975 9147 4000 9128
TIME...MOT...LOC 2144Z 298DEG 22KT 3992 9128 3973 9142 3972 9182 

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

$$

Elmore

1 follow-up statement

981 
WWUS53 KLSX 122220
SVSLSX

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

ILC001-MOC127-122230-
/O.CAN.KLSX.SV.W.0143.000000T0000Z-210812T2230Z/
Adams IL-Marion MO-
520 PM CDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ADAMS AND SOUTHERN
MARION COUNTIES IS CANCELLED...

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

LAT...LON 3966 9091 3952 9093 3951 9152 3961 9172
      3966 9171 3966 9159 3969 9128 3976 9118
      3976 9092
TIME...MOT...LOC 2220Z 270DEG 22KT 3983 9106 3964 9120 3963 9160 

$$

ILC149-MOC163-173-122230-
/O.CON.KLSX.SV.W.0143.000000T0000Z-210812T2230Z/
Pike IL-Ralls MO-Pike MO-
520 PM CDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT
FOR NORTHWESTERN PIKE COUNTY IN WEST CENTRAL ILLINOIS...NORTHERN
RALLS AND NORTHWESTERN PIKE COUNTIES IN NORTHEASTERN MISSOURI...

At 520 PM CDT, severe thunderstorms were located along a line
extending from near Beverly to 9 miles southwest of Barry to near
Rensselaer, moving east at 25 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
  Barry and New London.

This includes Interstate 72 between exits 10 and 20.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3966 9091 3952 9093 3951 9152 3961 9172
      3966 9171 3966 9159 3969 9128 3976 9118
      3976 9092
TIME...MOT...LOC 2220Z 270DEG 22KT 3983 9106 3964 9120 3963 9160 

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

$$

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, 4:50 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, 6:37 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Jefferson, Saint Charles, Saint Louis, City of Saint Louis	53 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.