Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 155, NWS St. Louis, MO

August 26, 2021Saint Louis County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 26, 2021, 3:10 PM CDT for Saint Louis County, Missouri. It was in force for 50 min. 5 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 26, 2021, 3:10 PM CDT (20:10 UTC)
Expired
Aug 26, 2021, 4:00 PM CDT
In force
50 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Saint Louis County, MO

The radar

The St Louis radar (KLSX), 22 km from the middle of the area, began a volume at 20:09 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 26, 3:17 PM CDTTSTM WND DMG1 E Maryland Heights, MOMULTIPLE SMALL TO MEDIUM SIZE TREE LIMBS SNAPPED/DOWNED.
Aug 26, 3:17 PM CDTTSTM WND DMG2 Ese Maryland Heights, MOCORRECTS PREVIOUS TSTM WND DMG REPORT FROM 2 ESE MARYLAND HEIGHTS. LARGE TREE DOWN NEAR 270 AND DORSETT ROAD. TIME ESTIMATED FROM RADAR.
Aug 26, 3:17 PM CDTTSTM WND DMG2 Se Maryland Heights, MOAPPROXIMATELY 12 INCH DIAMETER TREE LIMB SNAPPED.
Aug 26, 3:50 PM CDTTSTM WND DMG1 Wnw Brentwood, MOSEVERAL LARGE TREES UPROOTED.
Aug 26, 3:50 PM CDTTSTM WND DMG1 Wnw Brentwood, MOLARGE TREE LIMBS DOWN IN TILLES PARK.

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

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 8.2 hours before the alert went out and 225 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 2021-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1067 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 2021-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 89 square meters per square second.1939Sfc1 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
1067 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
954 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
89 m²/s²
0-3 km storm-relative helicity
118 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.6

Open this sounding in Storm Lab

The text

As transmitted.

958 
WUUS53 KLSX 262010
SVRLSX
MOC189-262100-
/O.NEW.KLSX.SV.W.0155.210826T2010Z-210826T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
310 PM CDT Thu Aug 26 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Central St. Louis County in east central Missouri...

* Until 400 PM CDT.

* At 310 PM CDT, a severe thunderstorm was located over Creve Coeur,
  moving southwest at 15 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Kirkwood and Des Peres around 315 PM CDT.
  Chesterfield, Town and Country and Country Life Acres around 320 
  PM CDT.

This includes the following highways...
 Interstate 44 in Missouri near exit 277.
 Interstate 70 in Missouri near exit 231.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3871 9026 3865 9030 3862 9031 3855 9040
      3866 9059 3868 9060 3868 9056 3869 9053
      3873 9053 3876 9049 3877 9046 3879 9043
      3874 9025
TIME...MOT...LOC 2010Z 060DEG 12KT 3868 9045 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Glass
2 follow-up statements
615 
WWUS53 KLSX 262035
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
335 PM CDT Thu Aug 26 2021

MOC189-262100-
/O.CON.KLSX.SV.W.0155.000000T0000Z-210826T2100Z/
St. Louis MO-
335 PM CDT Thu Aug 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM CDT
FOR CENTRAL ST. LOUIS COUNTY...

At 334 PM CDT, a severe thunderstorm was located over Maryland
Heights, moving northwest at 5 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

This severe thunderstorm will remain over mainly rural areas of
central St. Louis County.

This includes the following highways...
 Interstate 44 in Missouri near exit 277.
 Interstate 70 in Missouri near exit 231.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3871 9026 3865 9030 3862 9031 3855 9040
      3866 9059 3868 9060 3868 9056 3869 9053
      3873 9053 3876 9049 3877 9046 3879 9043
      3874 9025
TIME...MOT...LOC 2034Z 146DEG 5KT 3874 9048 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

19
302 
WWUS53 KLSX 262052
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
352 PM CDT Thu Aug 26 2021

MOC189-262102-
/O.EXP.KLSX.SV.W.0155.000000T0000Z-210826T2100Z/
St. Louis MO-
352 PM CDT Thu Aug 26 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ST. LOUIS COUNTY WILL
EXPIRE AT 400 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 3871 9026 3865 9030 3862 9031 3855 9040
      3866 9059 3868 9060 3868 9056 3869 9053
      3873 9053 3876 9049 3877 9046 3879 9043
      3874 9025
TIME...MOT...LOC 2052Z 060DEG 12KT 3871 9054 

$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 2:25 PM CDTSevere Thunderstorm WarningLSXSaint Louis50 min
Aug 26, 3:46 PM CDTSevere Thunderstorm WarningLSXLincoln, Warren44 min
Aug 26, 5:28 PM CDTSevere Thunderstorm WarningLSXMarion25 min
Aug 26, 5:34 PM CDTSevere Thunderstorm WarningLSXAudrain, Monroe41 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.