Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 339, NWS St. Louis, MO

October 22, 2012Clinton County, Madison County, Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Oct 22, 2012, 11:38 AM CDT for Clinton County, Madison County, Saint Clair County, Illinois. It was in force for 37 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
Oct 22, 2012, 11:38 AM CDT (16:38 UTC)
Expired
Oct 22, 2012, 12:15 PM CDT
In force
37 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Clinton County, IL, Madison County, IL, Saint Clair County, IL

The radar

The St Louis radar (KLSX), 79 km from the middle of the area, began a volume at 16:41 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, 4.6 hours before the alert went out and 188 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 2012-10-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 620 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 12:00Z on 2012-10-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 103 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
620 J/kg
Mixed-layer CIN
-91 J/kg
Mixed-layer LCL
653 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

405 
WUUS53 KLSX 221638
SVRLSX
ILC027-119-163-221715-
/O.NEW.KLSX.SV.W.0339.121022T1638Z-121022T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1138 AM CDT MON OCT 22 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WEST CENTRAL CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...
  SOUTHEASTERN MADISON COUNTY IN SOUTHWEST ILLINOIS...
  NORTHEASTERN ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 1215 PM CDT

* AT 1137 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR O'FALLON...
  AND MOVING EAST AT 35 MPH.

  HAZARD...QUARTER SIZE HAIL.

  SOURCE...RADAR INDICATED.

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

* LOCATIONS IMPACTED INCLUDE...
  TROY...LEBANON...HIGHLAND...ST. JACOB...MARINE...TRENTON...
  AVISTON...SUMMERFIELD AND GRANTFORK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

&&

LAT...LON 3887 8960 3860 8959 3856 9001 3871 9007
TIME...MOT...LOC 1638Z 253DEG 30KT 3866 8990

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

$$

BRITT
2 follow-up statements
889 
WWUS53 KLSX 221652
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1152 AM CDT MON OCT 22 2012

ILC027-119-163-221715-
/O.CON.KLSX.SV.W.0339.000000T0000Z-121022T1715Z/
MADISON IL-ST. CLAIR IL-CLINTON IL-
1152 AM CDT MON OCT 22 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHWESTERN
CLINTON...NORTHEASTERN ST. CLAIR AND SOUTHEASTERN MADISON COUNTIES
UNTIL 1215 PM CDT...

AT 1150 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR ST. JACOB...
AND MOVING EAST AT 35 MPH.

HAZARD...QUARTER SIZE HAIL.

SOURCE...RADAR INDICATED.

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

LOCATIONS IMPACTED INCLUDE...
HIGHLAND...MARINE...TRENTON...AVISTON AND GRANTFORK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

&&

LAT...LON 3887 8960 3860 8959 3856 9001 3871 9007
TIME...MOT...LOC 1652Z 253DEG 30KT 3869 8976

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

$$

BRITT
702 
WWUS53 KLSX 221712
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1212 PM CDT MON OCT 22 2012

ILC027-119-163-221719-
/O.EXP.KLSX.SV.W.0339.000000T0000Z-121022T1715Z/
MADISON IL-ST. CLAIR IL-CLINTON IL-
1212 PM CDT MON OCT 22 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CLINTON...
NORTHEASTERN ST. CLAIR AND SOUTHEASTERN MADISON COUNTIES WILL EXPIRE
AT 1215 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
STRONG THUNDERSTORMS CONTINUE TO MOVE EAST ACROSS PARTS OF MADISON 
AND ST. CLAIR COUNTIES AND MAY CONTINUE TO PRODUCE HAIL UP TO NICKEL 
SIZE THROUGH 1230 PM CDT.

LAT...LON 3887 8960 3860 8959 3856 9001 3871 9007
TIME...MOT...LOC 1709Z 253DEG 30KT 3873 8959

$$

BRITT

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 22, 6:20 AM CDTSevere Thunderstorm WarningLSXAdams55 min
Oct 22, 6:56 AM CDTSevere Thunderstorm WarningLSXAdams, Pike49 min
Oct 22, 7:43 AM CDTSevere Thunderstorm WarningLSXPike47 min
Oct 22, 9:30 AM CDTSevere Thunderstorm WarningLSXGreene, Jersey, Macoupin45 min
Oct 22, 10:34 AM CDTSevere Thunderstorm WarningLSXMadison41 min
Oct 22, 2:04 PM CDTSevere Thunderstorm WarningLSXMadison, Saint Clair24 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.