Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 9, NWS St. Louis, MO

March 27, 2021Greene County, Macoupin County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Mar 27, 2021, 4:47 PM CDT for Greene County, Macoupin County, Illinois. It was in force for 43 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, 4:47 PM CDT (21:47 UTC)
Expired
Mar 27, 2021, 5:30 PM CDT
In force
43 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Greene County, IL, Macoupin County, IL

The radar

The St Louis radar (KLSX), 97 km from the middle of the area, began a volume at 21:47 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
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, 9.8 hours before the alert went out and 151 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.

384 
WUUS53 KLSX 272147
SVRLSX
ILC061-117-272230-
/O.NEW.KLSX.SV.W.0009.210327T2147Z-210327T2230Z/

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

The National Weather Service in St Louis has issued a

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

* Until 530 PM CDT.

* At 447 PM CDT, a severe thunderstorm was located near White Hall,
  moving east at 60 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, White Hall, Carrollton, Girard, Roodhouse, Greenfield,
  Palmyra, Athensville, Patterson, Wrights, Eldred, Hillview,
  Modesto, Scottville, Belltown, Berdan, Haypress, Barrow and
  Walkersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3945 8970 3925 9057 3946 9056 3952 9039
      3952 8970
TIME...MOT...LOC 2147Z 248DEG 50KT 3943 9034 

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

BRC
1 follow-up statement
139 
WWUS53 KLSX 272209
SVSLSX

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

ILC061-117-272230-
/O.CON.KLSX.SV.W.0009.000000T0000Z-210327T2230Z/
Greene IL-Macoupin IL-
509 PM CDT Sat Mar 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT
FOR NORTHEASTERN GREENE AND NORTHERN MACOUPIN COUNTIES...

At 509 PM CDT, a severe thunderstorm was located near Palmyra, moving
east at 55 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, Greenfield, Palmyra, Athensville, Modesto and
Scottville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3945 8970 3933 9023 3952 9033 3952 8970
TIME...MOT...LOC 2209Z 250DEG 48KT 3951 8999 

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

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, 4:52 PM CDTSevere Thunderstorm WarningLSXJersey, Madison38 min
Mar 27, 5:18 PM CDTSevere Thunderstorm WarningLSXMacoupin, Montgomery42 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; radar from the NEXRAD Level II archive.