Alert archive / Missouri / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 231, NWS St. Louis, MO

August 4, 20124 counties in Missouri; Madison County, Monroe County, Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 4, 2012, 10:22 PM CDT for 4 counties in Missouri; Madison County, Monroe County, Saint Clair County, Illinois. It was in force for 38 min. 4 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
Aug 4, 2012, 10:22 PM CDT (03:22 UTC)
Expired
Aug 4, 2012, 11:00 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 Madison County, IL, Monroe County, IL, Saint Clair County, IL, City of Saint Louis, MO, Jefferson County, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 38 km from the middle of the area, began a volume at 03:25 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
Aug 4, 10:25 PM CDTTSTM WND DMGChesterfield, MO3-6 INCH DIAMETER TREE LIMBS BLOWN DOWN
Aug 4, 10:25 PM CDTTSTM WND GST 65Maryland Heights, MO
Aug 4, 10:35 PM CDTTSTM WND GST 52Kirkwood, MO
Aug 4, 10:39 PM CDTTSTM WND DMG2 N Byrnes Mill, MOSEVERAL TREES BLOWN DOWN.

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
Aug 4, 6:12 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 3.4 hours before the alert went out and 216 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 2012-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 857 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 2012-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 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
857 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
1700 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
210 m²/s²
Significant tornado parameter
0.2
Supercell composite
3.0

Open this sounding in Storm Lab

The text

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

851 
WUUS53 KLSX 050322
SVRLSX
ILC119-133-163-MOC099-183-189-510-050400-
/O.NEW.KLSX.SV.W.0231.120805T0322Z-120805T0400Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1022 PM CDT SAT AUG 4 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN MADISON COUNTY IN SOUTHWEST ILLINOIS...
  EXTREME NORTH CENTRAL MONROE COUNTY IN SOUTHWEST ILLINOIS...
  NORTHWESTERN ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...
  NORTHEASTERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI...
  SOUTHERN ST. CHARLES COUNTY IN EAST CENTRAL MISSOURI...
  ST. LOUIS COUNTY IN EAST CENTRAL MISSOURI...
  ST. LOUIS CITY IN EAST CENTRAL MISSOURI...

* UNTIL 1100 PM CDT

* AT 1016 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
  LINE EXTENDING FROM DARDENNE PRAIRIE TO DITTMER...AND MOVING EAST
  AT 45 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...
  CLARKSON VALLEY...ELLISVILLE...ST. PETERS...CHESTERFIELD...
  BALLWIN...HIGH RIDGE...MANCHESTER...ST. CHARLES...MURPHY...
  VALLEY PARK...TOWN AND COUNTRY...MARYLAND HEIGHTS...FENTON...
  DES PERES...CREVE COEUR...KIRKWOOD...SUNSET HILLS...FRONTENAC...
  BRIDGETON...WARSON WOODS...AND THE CITY OF ST. LOUIS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3884 8999 3844 9000 3845 9062 3883 9062
TIME...MOT...LOC 0321Z 266DEG 41KT 3875 9066 3835 9065

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

$$

TRUETT
2 follow-up statements
770 
WWUS53 KLSX 050349
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1049 PM CDT SAT AUG 4 2012

ILC119-133-163-MOC099-183-189-510-050400-
/O.CON.KLSX.SV.W.0231.000000T0000Z-120805T0400Z/
MADISON IL-MONROE IL-ST. CLAIR IL-JEFFERSON MO-ST. CHARLES MO-
ST. LOUIS MO-ST. LOUIS CITY MO-
1049 PM CDT SAT AUG 4 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR ST. LOUIS
CITY...ST. LOUIS...CENTRAL ST. CHARLES...NORTHEASTERN JEFFERSON...
NORTHWESTERN ST. CLAIR...EXTREME NORTH CENTRAL MONROE AND
SOUTHWESTERN MADISON COUNTIES UNTIL 1100 PM CDT...

AT 1044 PM CDT...A LINE OF SEVERE THUNDERSTORMS WAS LOCATED ALONG A
LINE EXTENDING FROM ST. CHARLES TO HOUSE SPRINGS...AND MOVING EAST AT
30 MPH.

HAZARD...60 MPH WIND GUSTS.

SOURCE...RADAR INDICATED...WITH A WEAKENING TREND NOTED IN THE HIGH
         WINDS.

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

LOCATIONS IMPACTED INCLUDE...
MURPHY...VALLEY PARK...TOWN AND COUNTRY...MARYLAND HEIGHTS...
FENTON...DES PERES...CREVE COEUR...BRIDGETON...KIRKWOOD...SUNSET
HILLS...FRONTENAC...WARSON WOODS...ST. 
ANN...OAKLAND...LADUE...CRESTWOOD...GLENDALE...OLIVETTE...OVERLAND...
LAMBERT FIELD...AND ST LOUIS CITY.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3884 8999 3844 9000 3845 9062 3883 9062
TIME...MOT...LOC 0347Z 264DEG 26KT 3882 9051 3842 9051

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

$$

TRUETT
067 
WWUS53 KLSX 050402
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1102 PM CDT SAT AUG 4 2012

ILC119-133-163-MOC099-183-189-510-050411-
/O.EXP.KLSX.SV.W.0231.000000T0000Z-120805T0400Z/
MADISON IL-MONROE IL-ST. CLAIR IL-JEFFERSON MO-ST. CHARLES MO-
ST. LOUIS MO-ST. LOUIS CITY MO-
1102 PM CDT SAT AUG 4 2012

...THE SEVERE THUNDERSTORM WARNING FOR ST. LOUIS CITY...
ST. LOUIS...SOUTHERN ST. CHARLES...NORTHEASTERN
JEFFERSON...NORTHWESTERN ST. CLAIR...EXTREME NORTH CENTRAL MONROE 
AND SOUTHWESTERN MADISON COUNTIES 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 OF 30 TO 40 MPH AND POCKETS OF HEAVY 
RAIN WILL CONTINUE OVER THE METRO AREA THROUGH 1130 PM. 

LAT...LON 3884 8999 3844 9000 3845 9062 3883 9062
TIME...MOT...LOC 0349Z 264DEG 26KT 3882 9049 3842 9049

$$

TRUETT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 8:30 PM CDTSevere Thunderstorm WarningLSXCallaway, Gasconade, Montgomery, Osage45 min
Aug 4, 8:47 PM CDTSevere Thunderstorm WarningLSXGasconade, Osage43 min
Aug 4, 9:07 PM CDTSevere Thunderstorm WarningLSXGasconade, Montgomery, Osage, Warren23 min
Aug 4, 9:20 PM CDTSevere Thunderstorm WarningLSXCrawford, Franklin, Gasconade, Warren, Washington40 min
Aug 4, 9:38 PM CDTSevere Thunderstorm WarningLSXFranklin, Jefferson, Saint Charles, Saint Louis, Warren, Washington67 min
Aug 4, 10:59 PM CDTSevere Thunderstorm WarningLSXJefferson, Sainte Genevieve46 min
Aug 4, 11:46 PM CDTSevere Thunderstorm WarningLSXLincoln, Saint Charles, Warren33 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2012Severe 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.