Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 304, NWS St. Louis, MO

September 7, 2012Randolph County, Saint Clair County, Washington County, Illinois; Sainte Genevieve County, Saint Francois County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Sep 7, 2012, 7:35 PM CDT for Randolph County, Saint Clair County, Washington County, Illinois; Sainte Genevieve County, Saint Francois County, Missouri. It was in force for 20 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
Sep 7, 2012, 7:35 PM CDT (00:35 UTC)
Expired
Sep 7, 2012, 7:55 PM CDT
In force
20 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Randolph County, IL, Saint Clair County, IL, Washington County, IL, Saint Francois County, MO, Sainte Genevieve County, MO

The radar

The St Louis radar (KLSX), 111 km from the middle of the area, began a volume at 00:38 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 watch it was issued in

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

IssuedProductOfficeLasted
Sep 7, 2:35 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.6 hours before the alert went out and 262 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 2012-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2012-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -113 square meters per square second.1939587897117Sfc1 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
723 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
-113 m²/s²
0-3 km storm-relative helicity
99 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.

797 
WUUS53 KLSX 080035
SVRLSX
ILC157-163-189-MOC186-187-080115-
/O.NEW.KLSX.SV.W.0304.120908T0035Z-120908T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
735 PM CDT FRI SEP 7 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  RANDOLPH COUNTY IN SOUTHWEST ILLINOIS...
  SOUTHEASTERN ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...
  SOUTHWESTERN WASHINGTON COUNTY IN SOUTH CENTRAL ILLINOIS...
  SOUTHEASTERN STE. GENEVIEVE COUNTY IN SOUTHEAST MISSOURI...
  SOUTHERN ST. FRANCOIS COUNTY IN SOUTHEAST MISSOURI...

* UNTIL 815 PM CDT

* AT 734 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
  LINE EXTENDING FROM NEW DESIGN TO RED BUD TO STE. GENEVIEVE TO KNOB
  LICK...AND MOVING EAST AT 35 MPH.

  HAZARD...60 MPH WIND GUSTS.

  SOURCE...RADAR INDICATED.

  IMPACT...MINOR TREE DAMAGE...WITH LIMBS UP TO ONE INCH IN DIAMETER
           BROKEN.

* LOCATIONS IMPACTED INCLUDE...
  CHESTER...SPARTA...BALDWIN...WOMAC...ST. MARY...BREMEN...MARISSA...
  TILDEN...STEELEVILLE...PERCY...COULTERVILLE...ELLIS GROVE...
  PRESTON...WALSH...KASKASKIA...NEW PALESTINE...MINNITH...HOUSTON...
  LENZBURG AND BLAIR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3821 8959 3795 8959 3780 8968 3784 8974
      3785 8979 3788 8981 3790 8985 3787 8990
      3787 8994 3782 8999 3764 9014 3764 9028
      3794 8997 3818 8988 3828 8993 3830 8990
      3829 8935 3821 8934
TIME...MOT...LOC 0035Z 270DEG 31KT 3831 9009 3815 8997
          3796 9002 3771 9037

HAIL...<.75IN
WIND...60 MPH

$$

TRUETT
1 follow-up statement
185 
WWUS53 KLSX 080055
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
755 PM CDT FRI SEP 7 2012

ILC157-163-189-MOC186-187-080103-
/O.CAN.KLSX.SV.W.0304.000000T0000Z-120908T0115Z/
RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL-STE. GENEVIEVE MO-
ST. FRANCOIS MO-
755 PM CDT FRI SEP 7 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ST. FRANCOIS...
SOUTHEASTERN STE. GENEVIEVE...SOUTHWESTERN WASHINGTON...SOUTHEASTERN
ST. CLAIR AND RANDOLPH COUNTIES IS CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAS WEAKENED BELOW
SEVERE LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR 
PROPERTY.  HOWEVER MODERATE AND HEAVY RAIN IS STILL POSSIBLE WITH 
THESE THUNDERSTORMS ACROSS RANDOLPH...SOUTHWEST WARNINGTON...AND 
SOUTHEAST ST CLAIR COUNTIES THROUGH 830 PM.  

LAT...LON 3821 8959 3795 8959 3780 8968 3784 8974
      3785 8979 3788 8981 3790 8985 3787 8990
      3787 8994 3782 8999 3764 9014 3764 9028
      3794 8997 3818 8988 3828 8993 3830 8990
      3829 8935 3821 8934
TIME...MOT...LOC 0053Z 270DEG 31KT 3831 8989 3815 8977
          3796 8982 3771 9017

$$

TRUETT

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 7:03 PM CDTFlash Flood WarningLSXBond3 hr
Sep 7, 7:03 PM CDTSevere Thunderstorm WarningLSXMonroe, Randolph, Saint Clair42 min
Sep 7, 7:06 PM CDTTornado WarningLSXWashington24 min
Sep 7, 7:25 PM CDTAreal Flood AdvisoryLSXMadison, Saint Clair6 hr
Sep 7, 7:11 PM CDTSevere Thunderstorm WarningLSXIron, Madison, Reynolds49 min
Sep 7, 8:09 PM CDTAreal Flood AdvisoryLSXSaint Francois, Washington6 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2012Severe Thunderstorm Warnings in Missouri, 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.