Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 115, NWS St. Louis, MO

April 28, 2012Clinton County, Saint Clair County, Washington County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 28, 2012, 4:56 PM CDT for Clinton County, Saint Clair County, Washington County, Illinois. It was in force for 49 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
Apr 28, 2012, 4:56 PM CDT (21:56 UTC)
Expired
Apr 28, 2012, 5:45 PM CDT
In force
49 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.75 in
Wind
60.0 mph

Counties Clinton County, IL, Saint Clair County, IL, Washington County, IL

The radar

The St Louis radar (KLSX), 116 km from the middle of the area, began a volume at 21:56 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
Apr 28, 5:11 PM CDTHAIL 0.25Okawville, ILFROM THE SHERIFF DEPT.
Apr 28, 5:20 PM CDTHAIL 4.5Okawville, ILCORRECTED FOR TIME
Apr 28, 5:55 PM CDTHAIL 1.753 N Venedy, IL

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
Apr 28, 1:48 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.9 hours before the alert went out and 213 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 2012-04-28Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 681 square meters per square second.19395878Sfc1 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
1019 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
681 m²/s²
0-3 km storm-relative helicity
811 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

395 
WUUS53 KLSX 282156
SVRLSX
ILC027-163-189-282245-
/O.NEW.KLSX.SV.W.0115.120428T2156Z-120428T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
456 PM CDT SAT APR 28 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EXTREME SOUTHWESTERN CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...
  EAST CENTRAL ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...
  WASHINGTON COUNTY IN SOUTH CENTRAL ILLINOIS...

* UNTIL 545 PM CDT

* AT 452 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR MASCOUTAH...
  AND MOVING EAST AT 35 MPH.

  HAZARD...GOLF BALL SIZE HAIL AND 60 MPH WIND GUSTS.

  SOURCE...RADAR INDICATED.

  IMPACT...DAMAGE TO VEHICLES...ROOFS AND WINDOWS. MINOR TREE
           DAMAGE...WITH LIMBS UP TO ONE INCH IN DIAMETER BROKEN.

* LOCATIONS IMPACTED INCLUDE...
  NASHVILLE...NEW MEMPHIS...OKAWVILLE...ASHLEY...ST. LIBORY...
  JOHANNISBURG...VENEDY...STONE CHURCH...FROGTOWN...ADDIEVILLE...
  CORDES...HUEGELY...BEAUCOUP...RICHVIEW AND RADOM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM IS PRODUCING LARGE HAIL. SEEK SHELTER NOW INSIDE A STURDY
STRUCTURE AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 3821 8915 3840 8989 3852 8983 3839 8914
TIME...MOT...LOC 2156Z 285DEG 30KT 3848 8973

HAIL...1.75IN
WIND...60 MPH

$$

BYRD

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 28, 2:26 PM CDTSevere Thunderstorm WarningLSXCalhoun49 min
Apr 28, 3:05 PM CDTSevere Thunderstorm WarningLSXCalhoun, Jersey, Madison40 min
Apr 28, 3:45 PM CDTSevere Thunderstorm WarningLSXClinton, Madison, Saint Clair45 min
Apr 28, 3:59 PM CDTTornado WarningLSXSaint Clair31 min
Apr 28, 4:22 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington38 min
Apr 28, 4:28 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington47 min
Apr 28, 5:13 PM CDTSevere Thunderstorm WarningLSXClinton, Marion, Washington47 min
Apr 28, 5:38 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington37 min
Apr 28, 5:50 PM CDTSevere Thunderstorm WarningLSXCalhoun40 min
Apr 28, 6:01 PM CDTTornado WarningLSXMadison, Saint Clair29 min
Apr 28, 6:10 PM CDTSevere Thunderstorm WarningLSXMonroe34 min
Apr 28, 6:17 PM CDTSevere Thunderstorm WarningLSXClinton, Washington33 min
Apr 28, 6:27 PM CDTSevere Thunderstorm WarningLSXMadison, Saint Clair48 min
Apr 28, 6:35 PM CDTSevere Thunderstorm WarningLSXFayette, Marion25 min
Apr 28, 6:53 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington52 min
Apr 28, 6:58 PM CDTSevere Thunderstorm WarningLSXFayette, Marion32 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.