Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 38, NWS St. Louis, MO

May 3, 2021Montgomery County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at May 3, 2021, 7:32 PM CDT for Montgomery County, Illinois. It was in force for 21 min. 2 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: May 3, 2021, 7:32 PM CDT (00:32 UTC)
Expired: May 3, 2021, 7:53 PM CDT
In force: 21 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.75 in
Wind: 50.0 mph

County Montgomery County, IL

The radar

The Lincoln radar (KILX), 94 km from the middle of the area, began a volume at 00:34 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
May 3, 7:33 PM CDT	HAIL 1.25	1 Nne Wenonah, IL
May 3, 7:35 PM CDT	HAIL 1.75	3 Wnw Wenonah, IL

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

The watch it was issued in

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

Issued	Product	Office	Lasted
May 3, 2:47 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.5 hours before the alert went out and 111 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: 758 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 843 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: 74 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

As transmitted.

019 
WUUS53 KLSX 040032
SVRLSX
ILC135-040115-
/O.NEW.KLSX.SV.W.0038.210504T0032Z-210504T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
732 PM CDT Mon May 3 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  East central Montgomery County in south central Illinois...

* Until 815 PM CDT.

* At 732 PM CDT, a severe thunderstorm was located near Nokomis,
  moving east at 40 mph.

  HAZARD...Golf ball size hail.

  SOURCE...Trained weather spotters.

  IMPACT...People and animals outdoors will be injured. Expect 
           damage to roofs, siding, windows, and vehicles.

* Locations impacted include...
  Nokomis, Coalton, Ohlman and Wenonah. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3929 8939 3935 8938 3935 8914 3926 8914
TIME...MOT...LOC 0032Z 274DEG 35KT 3934 8927 

HAIL...1.75IN
WIND...<50MPH
 
$$

Glass

2 follow-up statements

464 
WWUS53 KLSX 040041
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
741 PM CDT Mon May 3 2021

ILC135-040115-
/O.CON.KLSX.SV.W.0038.000000T0000Z-210504T0115Z/
Montgomery IL-
741 PM CDT Mon May 3 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM CDT
FOR EAST CENTRAL MONTGOMERY COUNTY...

At 741 PM CDT, a severe thunderstorm was located near Nokomis, moving
east at 35 mph.

HAZARD...Two inch hail.

SOURCE...Trained weather spotters.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Nokomis and Ohlman. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3929 8928 3935 8926 3935 8914 3926 8914
TIME...MOT...LOC 0041Z 289DEG 31KT 3932 8920 

HAIL...2.00IN
WIND...<50MPH
 
$$

Glass

344 
WWUS53 KLSX 040053
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
753 PM CDT Mon May 3 2021

ILC135-040103-
/O.CAN.KLSX.SV.W.0038.000000T0000Z-210504T0115Z/
Montgomery IL-
753 PM CDT Mon May 3 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MONTGOMERY COUNTY
IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM CDT for
south central Illinois.

LAT...LON 3929 8928 3935 8926 3935 8914 3926 8914
TIME...MOT...LOC 0052Z 274DEG 35KT 3931 8904 

$$

Glass

The office that day

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

Issued	Product	Office	Counties	Lasted
May 3, 7:39 PM CDT	Severe Thunderstorm Warning	LSX	Bond, Macoupin, Montgomery	51 min

Nearby

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.