Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 117, NWS St. Louis, MO

July 9, 2021Knox County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 9, 2021, 9:00 PM CDT for Knox County, Missouri. It was in force for 45 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
Jul 9, 2021, 9:00 PM CDT (02:00 UTC)
Expired
Jul 9, 2021, 9:45 PM CDT
In force
45 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Knox County, MO

The radar

The St Louis radar (KLSX), 199 km from the middle of the area, began a volume at 02:00 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 9, 8:18 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.0 hours before the alert went out and 222 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, Davenport, at 00:00Z on 2021-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2021-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1111 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
114 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

215 
WUUS53 KLSX 100200
SVRLSX
MOC103-100245-
/O.NEW.KLSX.SV.W.0117.210710T0200Z-210710T0245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
900 PM CDT Fri Jul 9 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Western Knox County in northeastern Missouri...

* Until 945 PM CDT.

* At 900 PM CDT, a severe thunderstorm was located near Brashear,
  moving south at 25 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Edina around 915 PM CDT.

Other locations in the path of this severe thunderstorm include
Plevna.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 200 AM CDT for northeastern
Missouri.

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

&&

LAT...LON 3996 9201 3995 9204 3996 9234 4030 9235
      4030 9227
TIME...MOT...LOC 0200Z 337DEG 22KT 4021 9235 

HAIL...1.25IN
WIND...60MPH
 
$$

Elmore
1 follow-up statement
541 
WWUS53 KLSX 100223
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
923 PM CDT Fri Jul 9 2021

MOC103-100245-
/O.CON.KLSX.SV.W.0117.000000T0000Z-210710T0245Z/
Knox MO-
923 PM CDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM CDT
FOR WESTERN KNOX COUNTY...

At 922 PM CDT, a severe thunderstorm was located near Brashear,
moving southeast at 25 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...
  Plevna.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 200 AM CDT for northeastern
Missouri.

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

&&

LAT...LON 3996 9201 3995 9204 3996 9234 4030 9235
      4030 9227
TIME...MOT...LOC 0222Z 322DEG 20KT 4012 9233 

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

Elmore

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 8:21 PM CDTSevere Thunderstorm WarningLSXLewis, Marion39 min
Jul 9, 8:55 PM CDTSevere Thunderstorm WarningLSXMarion, Ralls50 min
Jul 9, 8:58 PM CDTSevere Thunderstorm WarningLSXSaint Charles, Saint Louis62 min
Jul 9, 9:08 PM CDTAreal Flood AdvisoryLSXLewis, Marion32 min
Jul 9, 9:10 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis, Marion, Shelby65 min
Jul 9, 9:14 PM CDTSevere Thunderstorm WarningLSXSaint Louis, City of Saint Louis48 min
Jul 9, 9:36 PM CDTSevere Thunderstorm WarningLSXMarion, Monroe, Pike, Ralls, Shelby54 min
Jul 9, 9:40 PM CDTFlash Flood WarningLSXLewis, Marion3 hr
Jul 9, 10:10 PM CDTSevere Thunderstorm WarningLSXAudrain, Lincoln, Monroe, Pike, Ralls50 min
Jul 9, 10:32 PM CDTSevere Thunderstorm WarningLSXMonroe, Shelby23 min
Jul 9, 10:45 PM CDTSevere Thunderstorm WarningLSXAudrain, Callaway, Lincoln, Montgomery, Pike, Warren45 min
Jul 9, 11:08 PM CDTSevere Thunderstorm WarningLSXCallaway, Franklin, Gasconade, Montgomery, Osage, Warren67 min
Jul 9, 11:10 PM CDTRiver Flood WarningLSXLewis5 days
Jul 9, 11:10 PM CDTRiver Flood WarningLSXLewis32 hr
Jul 9, 11:10 PM CDTRiver Flood WarningLSXMarion4 days
Jul 9, 11:24 PM CDTAreal Flood AdvisoryLSXAudrain, Marion, Monroe, Pike, Ralls, Shelby3 hr
Jul 9, 11:28 PM CDTSevere Thunderstorm WarningLSXLincoln, Montgomery, Saint Charles, Warren47 min
Jul 9, 11:57 PM CDTAreal Flood AdvisoryLSXLincoln, Pike3 hr
Jul 9, 11:59 PM CDTSevere Thunderstorm WarningLSXFranklin, Jefferson, Lincoln, Saint Charles, Saint Louis, Warren and 1 more61 min
Jul 10, 12:26 AM CDTAreal Flood AdvisoryLSXLincoln, Saint Charles3 hr
Jul 10, 12:41 AM CDTAreal Flood AdvisoryLSXSaint Louis, City of Saint Louis3 hr
Jul 10, 12:42 AM CDTSevere Thunderstorm WarningLSXJefferson, Saint Louis, City of Saint Louis63 min
Jul 10, 1:08 AM CDTSevere Thunderstorm WarningLSXJefferson, Sainte Genevieve, Saint Francois, Washington52 min
Jul 10, 1:49 AM CDTRiver Flood WarningLSXMarion18 hr
Jul 10, 1:50 AM CDTSevere Thunderstorm WarningLSXIron, Madison, Sainte Genevieve, Saint Francois, Washington40 min
Jul 10, 2:29 AM CDTSevere Thunderstorm WarningLSXIron, Madison21 min
Jul 10, 6:14 AM CDTRiver Flood WarningLSXMonroe4 days
Jul 10, 8:30 AM CDTRiver Flood WarningLSXLincoln3 days
Jul 10, 2:15 PM CDTAreal Flood AdvisoryLSXSaint Charles, Saint Louis3 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.