Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 29, NWS St. Louis, MO

April 9, 2021Randolph County, Saint Clair County, Washington County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 9, 2021, 7:26 PM CDT for Randolph County, Saint Clair County, Washington County, Illinois. It was in force for 49 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
Apr 9, 2021, 7:26 PM CDT (00:26 UTC)
Expired
Apr 9, 2021, 8:15 PM CDT
In force
49 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Randolph County, IL, Saint Clair County, IL, Washington County, IL

The radar

The St Louis radar (KLSX), 91 km from the middle of the area, began a volume at 00:28 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 nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.4 hours before the alert went out and 231 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 00:00Z on 2021-04-10Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2021-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
1896 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
86 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

633 
WUUS53 KLSX 100026
SVRLSX
ILC157-163-189-100115-
/O.NEW.KLSX.SV.W.0029.210410T0026Z-210410T0115Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southwestern Washington County in south central Illinois...
  Northeastern Randolph County in southwestern Illinois...
  Southeastern St. Clair County in southwestern Illinois...

* Until 815 PM CDT.

* At 725 PM CDT, a severe thunderstorm was located over Sparta,
  moving northeast at 15 mph.

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

  SOURCE...Public.

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

* Locations impacted include...
  Freeburg, Sparta, New Athens, Marissa, Coulterville, Tilden, Lively
  Grove, Baldwin, Eden, St. Libory, Prairie, Lenzburg, Johannisburg,
  Fayetteville, Addieville, Houston, Venedy, Elkton and Stone Church.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3822 8955 3822 8959 3810 8960 3812 8996
      3822 8994 3822 8990 3823 8990 3827 8993
      3829 8992 3828 8991 3828 8990 3831 8992
      3846 8988 3843 8971 3842 8970 3843 8968
      3840 8947
TIME...MOT...LOC 0025Z 212DEG 12KT 3815 8975 

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

BRC
2 follow-up statements
051 
WWUS53 KLSX 100045
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
745 PM CDT Fri Apr 9 2021

ILC157-100053-
/O.CAN.KLSX.SV.W.0029.000000T0000Z-210410T0115Z/
Randolph IL-
745 PM CDT Fri Apr 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN RANDOLPH COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3822 8955 3822 8990 3823 8990 3827 8993
      3829 8992 3828 8991 3828 8990 3831 8992
      3846 8988 3843 8971 3842 8970 3843 8968
      3840 8947
TIME...MOT...LOC 0043Z 212DEG 12KT 3820 8971 

$$

ILC163-189-100115-
/O.CON.KLSX.SV.W.0029.000000T0000Z-210410T0115Z/
Washington IL-St. Clair IL-
745 PM CDT Fri Apr 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM CDT
FOR SOUTHWESTERN WASHINGTON AND SOUTHEASTERN ST. CLAIR COUNTIES...

At 743 PM CDT, a severe thunderstorm was located over Tilden, moving
northeast at 15 mph.

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

SOURCE...Public. At 728 PM...wind damage to trees was reported in 
         Coulterville, IL. 

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

Locations impacted include...
Freeburg, New Athens, Marissa, Lively Grove, St. Libory, Lenzburg,
Johannisburg, Fayetteville, Addieville, Venedy, Elkton and Stone
Church.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3822 8955 3822 8990 3823 8990 3827 8993
      3829 8992 3828 8991 3828 8990 3831 8992
      3846 8988 3843 8971 3842 8970 3843 8968
      3840 8947
TIME...MOT...LOC 0043Z 212DEG 12KT 3820 8971 

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

BRC
409 
WWUS53 KLSX 100106
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
806 PM CDT Fri Apr 9 2021

ILC163-189-100115-
/O.EXP.KLSX.SV.W.0029.000000T0000Z-210410T0115Z/
Washington IL-St. Clair IL-
806 PM CDT Fri Apr 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WASHINGTON AND
SOUTHEASTERN ST. CLAIR COUNTIES WILL EXPIRE AT 815 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds are still possible with
this thunderstorm.

LAT...LON 3822 8955 3822 8990 3823 8990 3827 8993
      3829 8992 3828 8991 3828 8990 3831 8992
      3846 8988 3843 8971 3842 8970 3843 8968
      3840 8947
TIME...MOT...LOC 0105Z 212DEG 12KT 3825 8967 

$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 10:09 AM CDTWind AdvisoryLSXAdams, Bond, Brown, Calhoun, Greene, Jersey and 4 more14 hr
Apr 10, 2:26 PM CDTRiver Flood WarningLSXBrown6 days

Nearby

Severe 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.