Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 92, NWS St. Louis, MO

April 15, 2012Monroe County, Saint Clair County, Illinois; Jefferson County, Saint Louis County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 15, 2012, 7:52 PM CDT for Monroe County, Saint Clair County, Illinois; Jefferson County, Saint Louis County, Missouri. It was in force for 38 min. 1 report 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 15, 2012, 7:52 PM CDT (00:52 UTC)
Expired
Apr 15, 2012, 8:30 PM CDT
In force
38 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Monroe County, IL, Saint Clair County, IL, Jefferson County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 65 km from the middle of the area, began a volume at 00:53 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 15, 7:52 PM CDTTSTM WND DMGBarnhart, MOFIRE DISPATCH REPORTS THAT A POWER LINE WAS BLOWN OVER WITH STORMS. TIME ESTIMATED WITH RADAR.

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 15, 4:42 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.9 hours before the alert went out and 245 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 2012-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 502 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 2012-04-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 square meters per square second.1939587897Sfc1 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
502 J/kg
Mixed-layer CIN
-103 J/kg
Mixed-layer LCL
972 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
388 m²/s²
Significant tornado parameter
0.8
Supercell composite
5.6

Open this sounding in Storm Lab

The text

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

465 
WUUS53 KLSX 160052
SVRLSX
ILC133-163-MOC099-189-160130-
/O.NEW.KLSX.SV.W.0092.120416T0052Z-120416T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
752 PM CDT SUN APR 15 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MONROE COUNTY IN SOUTHWEST ILLINOIS...
  ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...
  EASTERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI...
  SOUTH CENTRAL ST. LOUIS COUNTY IN EAST CENTRAL MISSOURI...

* UNTIL 830 PM CDT

* AT 749 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
  LINE EXTENDING FROM ARNOLD TO OLYMPIAN VILLAGE...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...
  CRYSTAL CITY...ARNOLD...OAKVILLE...MEHLVILLE...LEMAY...COLUMBIA...
  DUPO...WATERLOO...CAHOKIA...MILLSTADT...CENTREVILLE...BELLEVILLE...
  SWANSEA...FAIRVIEW HEIGHTS...O'FALLON...FREEBURG...SHILOH...SCOTT
  AFB...LEBANON AND MASCOUTAH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH ONE IS NOT
IMMEDIATELY LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE
TO A PLACE OF SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT
OR SMALL INTERIOR ROOM.

&&

LAT...LON 3825 8979 3822 8990 3822 9004 3817 9004
      3811 9024 3813 9025 3809 9029 3810 9033
      3806 9039 3802 9048 3848 9047 3854 9027
      3853 9026 3855 9025 3866 8984 3866 8979
TIME...MOT...LOC 0051Z 250DEG 32KT 3846 9040 3809 9039

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

$$

TRUETT
3 follow-up statements
386 
WWUS53 KLSX 160107
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
807 PM CDT SUN APR 15 2012

MOC099-189-160117-
/O.CAN.KLSX.SV.W.0092.000000T0000Z-120416T0130Z/
JEFFERSON MO-ST. LOUIS MO-
807 PM CDT SUN APR 15 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL ST. LOUIS AND
EASTERN JEFFERSON COUNTIES IS CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE 
WARNED AREA.

LAT...LON 3815 9025 3853 9026 3855 9025 3866 8984
      3865 8979 3831 8979
TIME...MOT...LOC 0107Z 250DEG 32KT 3851 9023 3814 9022

$$

ILC133-163-160130-
/O.CON.KLSX.SV.W.0092.000000T0000Z-120416T0130Z/
MONROE IL-ST. CLAIR IL-
807 PM CDT SUN APR 15 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR ST. CLAIR AND
EASTERN MONROE COUNTIES UNTIL 830 PM CDT...

AT 806 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
LINE EXTENDING FROM DUPO TO 9 MILES NORTH OF BLOOMSDALE...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...
DUPO...WATERLOO...CAHOKIA...MILLSTADT...CENTREVILLE...BELLEVILLE...
FAIRVIEW HEIGHTS...SWANSEA...O'FALLON...FREEBURG...SHILOH...SCOTT
AFB...LEBANON...MASCOUTAH...NEW DESIGN...SMITHTON...NEW ATHENS...
WARTBURG...BURKSVILLE AND BARR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH ONE IS NOT
IMMEDIATELY LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE
TO A PLACE OF SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT
OR SMALL INTERIOR ROOM.

&&

LAT...LON 3815 9025 3853 9026 3855 9025 3866 8984
      3865 8979 3831 8979
TIME...MOT...LOC 0107Z 250DEG 32KT 3851 9023 3814 9022

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

$$

TRUETT
428 
WWUS53 KLSX 160124
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
824 PM CDT SUN APR 15 2012

ILC133-160133-
/O.CAN.KLSX.SV.W.0092.000000T0000Z-120416T0130Z/
MONROE IL-
824 PM CDT SUN APR 15 2012

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN MONROE COUNTY IS
CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE 
WARNED AREA.

LAT...LON 3835 9006 3839 9012 3859 9011 3866 8984
      3865 8979 3843 8980
TIME...MOT...LOC 0123Z 250DEG 32KT 3860 9001 3839 9002

$$

ILC163-160130-
/O.CON.KLSX.SV.W.0092.000000T0000Z-120416T0130Z/
ST. CLAIR IL-
824 PM CDT SUN APR 15 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR CENTRAL ST.
CLAIR COUNTY UNTIL 830 PM CDT...

AT 822 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
LINE EXTENDING FROM FAIRVIEW HEIGHTS TO SMITHTON...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...
BELLEVILLE...SWANSEA...AND FREEBURG.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH ONE IS NOT
IMMEDIATELY LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE
TO A PLACE OF SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT
OR SMALL INTERIOR ROOM.

&&

LAT...LON 3835 9006 3839 9012 3859 9011 3866 8984
      3865 8979 3843 8980
TIME...MOT...LOC 0123Z 250DEG 32KT 3860 9001 3839 9002

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

$$

TRUETT
190 
WWUS53 KLSX 160131
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
831 PM CDT SUN APR 15 2012

ILC163-160140-
/O.EXP.KLSX.SV.W.0092.000000T0000Z-120416T0130Z/
ST. CLAIR IL-
831 PM CDT SUN APR 15 2012

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ST. CLAIR COUNTY HAS
EXPIRED...

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 GUSTY WINDS AND HEAVY RAIN ARE STILL POSSIBLE WITH
THESE THUNDERSTORMS AS THEY MOVE INTO THE LEBANON...OFALLON.... 
SHILOH...AND SCOTT AIR FORCE BASE AREAS THROUGH 9 PM.

IN ADDITION...STRONG THUNDERSTORMS MAY REDEVELOP...AND A TORNADO 
WATCH REMAINS IN EFFECT UNTIL 12 MIDNIGHT.

LAT...LON 3835 9006 3839 9012 3859 9011 3866 8984
      3865 8979 3843 8980
TIME...MOT...LOC 0130Z 250DEG 32KT 3862 8993 3841 8995

$$

TRUETT

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 15, 7:38 PM CDTSevere Thunderstorm WarningLSXJersey, Madison32 min
Apr 15, 8:01 PM CDTSevere Thunderstorm WarningLSXJersey, Macoupin, Madison30 min
Apr 16, 6:19 AM CDTRiver Flood WarningLSXSaint Charles6 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.