Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 157, NWS St. Louis, MO

August 26, 2021Greene County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 26, 2021, 4:38 PM CDT for Greene County, Illinois. It was in force for 52 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
Aug 26, 2021, 4:38 PM CDT (21:38 UTC)
Expired
Aug 26, 2021, 5:30 PM CDT
In force
52 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Greene County, IL

The radar

The St Louis radar (KLSX), 84 km from the middle of the area, began a volume at 21:40 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 12:00Z, 9.6 hours before the alert went out and 168 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°0°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.

450 
WUUS53 KLSX 262138
SVRLSX
ILC061-262230-
/O.NEW.KLSX.SV.W.0157.210826T2138Z-210826T2230Z/

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

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northern Greene County in southwestern Illinois...

* Until 530 PM CDT.

* At 438 PM CDT, a severe thunderstorm was located over White Hall,
  and is nearly stationary.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Greenfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3930 9015 3929 9033 3939 9054 3952 9044
      3952 9015
TIME...MOT...LOC 2138Z 316DEG 4KT 3943 9037 

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

$$

19
2 follow-up statements
129 
WWUS53 KLSX 262156
SVSLSX

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

ILC061-262230-
/O.CON.KLSX.SV.W.0157.000000T0000Z-210826T2230Z/
Greene IL-
456 PM CDT Thu Aug 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT
FOR NORTHERN GREENE COUNTY...

At 456 PM CDT, a severe thunderstorm was located near Carrollton,
moving southwest at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
White Hall, Roodhouse, Greenfield, Wrights, Walkersville, Belltown
and Berdan.

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 3930 9015 3929 9033 3939 9054 3950 9046
      3944 9015
TIME...MOT...LOC 2156Z 044DEG 12KT 3936 9041 

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

$$

19
531 
WWUS53 KLSX 262221
SVSLSX

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

ILC061-262231-
/O.EXP.KLSX.SV.W.0157.000000T0000Z-210826T2230Z/
Greene IL-
521 PM CDT Thu Aug 26 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN GREENE COUNTY WILL
EXPIRE AT 530 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 gusty
winds and heavy rain are still possible with this thunderstorm.

LAT...LON 3930 9015 3929 9033 3939 9054 3950 9046
      3944 9015
TIME...MOT...LOC 2221Z 316DEG 4KT 3934 9039 

$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 2:04 PM CDTSevere Thunderstorm WarningLSXMontgomery41 min
Aug 26, 2:45 PM CDTFlash Flood WarningLSXMontgomery4 hr
Aug 26, 5:28 PM CDTSevere Thunderstorm WarningLSXAdams25 min
Aug 26, 5:57 PM CDTSevere Thunderstorm WarningLSXBond, Fayette48 min
Aug 26, 6:54 PM CDTAreal Flood AdvisoryLSXBond3 hr

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.