Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS St. Louis, MO

March 27, 2021Macoupin County, Montgomery County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Mar 27, 2021, 5:18 PM CDT for Macoupin County, Montgomery County, Illinois. It was in force for 42 min. 3 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
Mar 27, 2021, 5:18 PM CDT (22:18 UTC)
Expired
Mar 27, 2021, 6:00 PM CDT
In force
42 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Macoupin County, IL, Montgomery County, IL

What was reported inside it

TimeReportWhereRemark
Mar 27, 5:24 PM CDTHAIL 0.75Virden, ILREPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:30 PM CDTHAIL 1Virden, ILCORRECTS PREVIOUS HAIL REPORT FROM VIRDEN. VIA BROADCAST MEDIA ON TWITTER.
Mar 27, 5:30 PM CDTHAIL 1Virden, ILVIA BROADCAST MEDIA ON TWITTER.

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.

IssuedProductOfficeLasted
Mar 27, 4:44 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.3 hours before the alert went out and 130 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 2021-03-27Temperature 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 12:00Z on 2021-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 369 square meters per square second.1939587897117136Sfc1 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
1078 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
369 m²/s²
0-3 km storm-relative helicity
384 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

379 
WUUS53 KLSX 272218
SVRLSX
ILC117-135-272300-
/O.NEW.KLSX.SV.W.0011.210327T2218Z-210327T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
518 PM CDT Sat Mar 27 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northeastern Macoupin County in southwestern Illinois...
  Northwestern Montgomery County in south central Illinois...

* Until 600 PM CDT.

* At 518 PM CDT, a severe thunderstorm was located near Girard,
  moving east at 50 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...
  Virden, Girard, White Oak, Farmersville, Palmyra, Nilwood and
  Modesto.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3937 8999 3952 8999 3952 8953 3940 8953
TIME...MOT...LOC 2218Z 256DEG 45KT 3948 8983 

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

BRC
2 follow-up statements
439 
WWUS53 KLSX 272240
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
540 PM CDT Sat Mar 27 2021

ILC117-272250-
/O.CAN.KLSX.SV.W.0011.000000T0000Z-210327T2300Z/
Macoupin IL-
540 PM CDT Sat Mar 27 2021

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

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

LAT...LON 3939 8970 3952 8970 3952 8953 3940 8953
TIME...MOT...LOC 2240Z 256DEG 45KT 3955 8948 

$$

ILC135-272300-
/O.CON.KLSX.SV.W.0011.000000T0000Z-210327T2300Z/
Montgomery IL-
540 PM CDT Sat Mar 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR NORTHWESTERN MONTGOMERY COUNTY...

At 540 PM CDT, a severe thunderstorm was located near Bulpitt, moving
east at 50 mph.

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

SOURCE...Trained weather spotters.

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

Locations impacted include...
White Oak and Farmersville. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3939 8970 3952 8970 3952 8953 3940 8953
TIME...MOT...LOC 2240Z 256DEG 45KT 3955 8948 

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

BRC
235 
WWUS53 KLSX 272252
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
552 PM CDT Sat Mar 27 2021

ILC135-272302-
/O.EXP.KLSX.SV.W.0011.000000T0000Z-210327T2300Z/
Montgomery IL-
552 PM CDT Sat Mar 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN MONTGOMERY COUNTY
WILL EXPIRE AT 600 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

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

LAT...LON 3939 8970 3952 8970 3952 8953 3940 8953
TIME...MOT...LOC 2252Z 256DEG 45KT 3958 8932 

$$

BRC

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 27, 4:23 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene, Pike52 min
Mar 27, 4:47 PM CDTSevere Thunderstorm WarningLSXGreene, Macoupin43 min
Mar 27, 4:52 PM CDTSevere Thunderstorm WarningLSXJersey, Madison38 min
Mar 27, 5:26 PM CDTSevere Thunderstorm WarningLSXMadison38 min
Mar 27, 6:56 PM CDTSevere Thunderstorm WarningLSXBond, Clinton, Madison, Saint Clair49 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.