Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 146, NWS St. Louis, MO

May 4, 2012Macoupin County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at May 4, 2012, 6:27 AM CDT for Macoupin County, Illinois. It was in force for 33 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
May 4, 2012, 6:27 AM CDT (11:27 UTC)
Expired
May 4, 2012, 7:00 AM CDT
In force
33 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Macoupin County, IL

The radar

The St Louis radar (KLSX), 81 km from the middle of the area, began a volume at 11:30 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
May 4, 6:40 AM CDTHAIL 0.25Gillespie, ILTIME ESTIMATED FROM RADAR.
May 4, 6:43 AM CDTHAIL 0.25Bunker Hill, IL
May 4, 6:51 AM CDTHAIL 0.5Dorchester, ILTIME ESTIMATED BY RADAR.

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

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 11.5 hours before the alert went out and 162 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 2012-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1905 joules per kilogram.LCLLFCEL10008507005003002001001 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 2012-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 square meters per square second.193958Sfc1 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
1905 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
1071 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

659 
WUUS53 KLSX 041127
SVRLSX
ILC117-041200-
/O.NEW.KLSX.SV.W.0146.120504T1127Z-120504T1200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
627 AM CDT FRI MAY 4 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN MACOUPIN COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 700 AM CDT

* AT 625 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR BUNKER
  HILL...AND MOVING EAST AT 35 MPH.

  HAZARD...QUARTER SIZE HAIL.

  SOURCE...RADAR INDICATED.

  IMPACT...MINOR DAMAGE TO VEHICLES...ROOFS AND WINDOWS.

* LOCATIONS IMPACTED INCLUDE...
  GILLESPIE...STAUNTON...BUNKER HILL...WILSONVILLE...BENLD...MOUNT
  OLIVE...ROYAL LAKES...PRUETT...DORCHESTER...WHITE CITY AND HORNSBY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE IMMEDIATELY FOR LARGE HAIL AND DEADLY CLOUD TO GROUND
LIGHTNING. SEEK SHELTER INSIDE A WELL-BUILT STRUCTURE. STAY AWAY FROM
WINDOWS.

TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN ST
LOUIS.

&&

LAT...LON 3900 8970 3900 9013 3913 9014 3921 8970
TIME...MOT...LOC 1127Z 263DEG 31KT 3907 8999

HAIL...1.00IN
WIND...<50 MPH

$$

TES
2 follow-up statements
524 
WWUS53 KLSX 041143
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
643 AM CDT FRI MAY 4 2012

ILC117-041200-
/O.CON.KLSX.SV.W.0146.000000T0000Z-120504T1200Z/
MACOUPIN IL-
643 AM CDT FRI MAY 4 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN
MACOUPIN COUNTY UNTIL 700 AM CDT...

AT 638 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR WILSONVILLE...
AND MOVING EAST AT 40 MPH.

HAZARD...QUARTER SIZE HAIL.

SOURCE...RADAR INDICATED.

IMPACT...MINOR DAMAGE TO VEHICLES...ROOFS AND WINDOWS.

LOCATIONS IMPACTED INCLUDE...
GILLESPIE...STAUNTON...BENLD...MOUNT OLIVE...WHITE CITY AND HORNSBY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE IMMEDIATELY FOR LARGE HAIL AND DEADLY CLOUD TO GROUND
LIGHTNING. SEEK SHELTER INSIDE A WELL-BUILT STRUCTURE. STAY AWAY FROM
WINDOWS.

TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN ST
LOUIS.

&&

LAT...LON 3900 8970 3900 9013 3913 9014 3921 8970
TIME...MOT...LOC 1143Z 262DEG 34KT 3908 8983

HAIL...1.00IN
WIND...<50 MPH

$$

TES
357 
WWUS53 KLSX 041157
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
657 AM CDT FRI MAY 4 2012

ILC117-041208-
/O.EXP.KLSX.SV.W.0146.000000T0000Z-120504T1200Z/
MACOUPIN IL-
657 AM CDT FRI MAY 4 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN MACOUPIN COUNTY WILL
EXPIRE AT 700 AM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
 HOWEVER SMALL HAIL IS STILL POSSIBLE WITH THIS THUNDERSTORM.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN ST LOUIS.

LAT...LON 3900 8970 3900 9013 3913 9014 3921 8970
TIME...MOT...LOC 1158Z 262DEG 34KT 3910 8965

$$

TES

The office that day

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

IssuedProductOfficeCountiesLasted
May 4, 4:03 AM CDTSevere Thunderstorm WarningLSXAdams, Brown42 min
May 4, 11:11 AM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington34 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2012Every severe thunderstorm warning in 2012

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.