Alert archive / Missouri / Tornado Warnings in 2011

Tornado Warning 31, NWS St. Louis, MO

April 19, 2011Jefferson County, Saint Louis County, Missouri; Monroe County, Illinois

NWS St. Louis, MO issued this tornado warning at Apr 19, 2011, 7:37 PM CDT for Jefferson County, Saint Louis County, Missouri; Monroe County, Illinois. It was in force for 36 min. 7 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 19, 2011, 7:37 PM CDT (00:37 UTC)
Expired
Apr 19, 2011, 8:13 PM CDT
In force
36 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon

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

The radar

The St Louis radar (KLSX), 41 km from the middle of the area, began a volume at 00:40 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 19, 7:39 PM CDTHAIL 0.7High Ridge, MO
Apr 19, 7:43 PM CDTHAIL 0.75Fenton, MO
Apr 19, 7:43 PM CDTHAIL 1Sunset Hills, MO
Apr 19, 7:50 PM CDTTSTM WND DMG1 Ese Fenton, MOMOBILE HOME SIDING TORN OFF
Apr 19, 7:50 PM CDTHAIL 1Sunset Hills, MO
Apr 19, 7:50 PM CDTHAIL 1.251 Ese Fenton, MOMOBILE HOME SIDING TORN OFF
Apr 19, 7:54 PM CDTHAIL 1Affton, MOI-270 AND TESSON FERRY

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 19, 1:00 PM CDTTornado WatchSPC10 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.6 hours before the alert went out and 247 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 2011-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2409 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 2011-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 370 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
2409 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
523 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
370 m²/s²
0-3 km storm-relative helicity
547 m²/s²
Significant tornado parameter
0.0
Supercell composite
24.4

Open this sounding in Storm Lab

The text

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

638 
WFUS53 KLSX 200037
TORLSX
ILC133-MOC099-189-200130-
/O.NEW.KLSX.TO.W.0031.110420T0037Z-110420T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
737 PM CDT TUE APR 19 2011

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN MONROE COUNTY IN SOUTHWEST ILLINOIS...
  NORTHERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI...
  SOUTHERN ST. LOUIS COUNTY IN EAST CENTRAL MISSOURI...

* UNTIL 830 PM CDT

* AT 736 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED NEAR HOUSE SPRINGS...OR NEAR BYRNES MILL...AND
  MOVING EAST AT 50 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MURPHY...BARNHART...VALLEY PARK...FENTON...ARNOLD...SUNSET HILLS...
  CRESTWOOD...OAKLAND...OAKVILLE...LAKESHIRE...MEHLVILLE...WEBSTER
  GROVES...AFFTON...SHREWSBURY...LEMAY...COLUMBIA...FOUNTAIN...
  PEERLESS PARK...KIMMSWICK AND NEW HANDOVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3836 9010 3824 9067 3849 9074 3860 9033
TIME...MOT...LOC 0038Z 249DEG 44KT 3843 9051

$$

GLASS
4 follow-up statements
784 
WWUS53 KLSX 200045
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
745 PM CDT TUE APR 19 2011

ILC133-MOC099-189-200130-
/O.CON.KLSX.TO.W.0031.000000T0000Z-110420T0130Z/
MONROE IL-JEFFERSON MO-ST. LOUIS MO-
745 PM CDT TUE APR 19 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHERN ST. LOUIS...
NORTHERN JEFFERSON AND NORTHWESTERN MONROE COUNTIES UNTIL 830 PM
CDT...

AT 740 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR HIGH RIDGE...MOVING EAST AT 50 MPH.

LARGE HAIL TO THE SIZE OF QUARTERS WILL ALSO OCCUR WITH THIS 
STORM.

LOCATIONS IMPACTED INCLUDE...
  ARNOLD...CRESTWOOD...OAKLAND...OAKVILLE...WEBSTER GROVES...
  LAKESHIRE...MEHLVILLE...AFFTON...SHREWSBURY...LEMAY...COLUMBIA...
  FOUNTAIN AND NEW HANDOVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3836 9010 3824 9067 3849 9074 3860 9033
TIME...MOT...LOC 0045Z 254DEG 45KT 3844 9040

$$

GLASS
748 
WWUS53 KLSX 200049
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
749 PM CDT TUE APR 19 2011

ILC133-MOC099-189-200130-
/O.CON.KLSX.TO.W.0031.000000T0000Z-110420T0130Z/
MONROE IL-JEFFERSON MO-ST. LOUIS MO-
749 PM CDT TUE APR 19 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHERN ST. LOUIS...
NORTHERN JEFFERSON AND NORTHWESTERN MONROE COUNTIES UNTIL 830 PM
CDT...

AT 744 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO.  THIS
TORNADO WAS LOCATED NEAR ARNOLD...MOVING EAST AT 50 MPH.

LOCATIONS IMPACTED INCLUDE...
  SHREWSBURY...LEMAY...COLUMBIA AND NEW HANDOVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. TAKE COVER NOW. MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID
WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR OUTDOORS...MOVE TO THE
CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3836 9010 3824 9067 3849 9074 3860 9033
TIME...MOT...LOC 0049Z 254DEG 45KT 3848 9031

$$

GLASS
586 
WWUS53 KLSX 200057
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
757 PM CDT TUE APR 19 2011

ILC133-MOC099-189-200130-
/O.CON.KLSX.TO.W.0031.000000T0000Z-110420T0130Z/
MONROE IL-JEFFERSON MO-ST. LOUIS MO-
757 PM CDT TUE APR 19 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHEASTERN ST. LOUIS...
NORTHEASTERN JEFFERSON AND NORTHWESTERN MONROE COUNTIES UNTIL 830 PM
CDT...

AT 753 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR DUPO...MOVING EAST AT 50 MPH.

LOCATIONS IMPACTED INCLUDE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3829 9040 3856 9039 3860 9033 3858 9031
      3857 9031 3857 9030 3853 9026 3852 9026
      3850 9023 3836 9010
TIME...MOT...LOC 0057Z 254DEG 45KT 3851 9019

$$

GLASS
117 
WWUS53 KLSX 200113
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
813 PM CDT TUE APR 19 2011

ILC133-MOC099-189-200123-
/O.CAN.KLSX.TO.W.0031.000000T0000Z-110420T0130Z/
MONROE IL-JEFFERSON MO-ST. LOUIS MO-
813 PM CDT TUE APR 19 2011

...THE TORNADO WARNING FOR SOUTHEASTERN ST. LOUIS...NORTHEASTERN
JEFFERSON AND NORTHWESTERN MONROE COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED AND MOVED OUT OF
THE WARNED AREA.

ADDITIONAL STRONG THUNDERSTORMS ARE STILL POSSIBLE...AND A TORNADO 
WATCH REMAINS IN EFFECT UNTIL 900 PM.

LAT...LON 3829 9040 3856 9039 3860 9033 3858 9031
      3857 9031 3857 9030 3853 9026 3852 9026
      3850 9023 3836 9010
TIME...MOT...LOC 0113Z 254DEG 45KT 3856 8994

$$

GLASS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 19, 7:03 PM CDTSevere Thunderstorm WarningLSXCrawford, Franklin, Washington42 min
Apr 19, 7:05 PM CDTAreal Flood AdvisoryLSXSaint Louis, City of Saint Louis5 hr
Apr 19, 7:17 PM CDTSevere Thunderstorm WarningLSXIron, Madison28 min
Apr 19, 7:18 PM CDTSevere Thunderstorm WarningLSXFranklin, Jefferson, Saint Louis42 min
Apr 19, 7:25 PM CDTTornado WarningLSXIron, Madison, Saint Francois40 min
Apr 19, 7:29 PM CDTSevere Thunderstorm WarningLSXIron, Madison, Sainte Genevieve, Saint Francois46 min
Apr 19, 7:30 PM CDTTornado WarningLSXSaint Louis, City of Saint Louis45 min
Apr 19, 7:34 PM CDTTornado WarningLSXMadison, Sainte Genevieve, Saint Francois41 min
Apr 19, 7:39 PM CDTTornado WarningLSXFranklin, Jefferson, Washington33 min
Apr 19, 7:48 PM CDTTornado WarningLSXMadison27 min
Apr 19, 7:54 PM CDTTornado WarningLSXSainte Genevieve36 min
Apr 19, 9:37 PM CDTSevere Thunderstorm WarningLSXSaint Charles, Saint Louis21 min
Apr 19, 7:35 PM CDTSevere Thunderstorm WarningLSXFayette, Montgomery40 min
Apr 19, 7:51 PM CDTTornado WarningLSXSaint Clair39 min
Apr 19, 7:56 PM CDTSevere Thunderstorm WarningLSXBond, Montgomery34 min
Apr 19, 8:00 PM CDTTornado WarningLSXBond, Clinton, Madison45 min
Apr 19, 8:02 PM CDTAreal Flood AdvisoryLSXBond, Macoupin, Montgomery4 hr
Apr 19, 8:18 PM CDTTornado WarningLSXRandolph, Saint Clair, Washington42 min
Apr 19, 8:25 PM CDTSevere Thunderstorm WarningLSXBond, Clinton, Madison, Saint Clair22 min
Apr 19, 8:33 PM CDTTornado WarningLSXFayette42 min
Apr 19, 8:33 PM CDTTornado WarningLSXBond, Clinton, Fayette, Marion, Washington57 min
Apr 19, 9:41 PM CDTRiver Flood WarningLSXFayette13 days

Nearby

Tornado Warnings in Missouri, 2011Tornado Warnings in Illinois, 2011Every tornado warning in 2011Tornadoes in 2011

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.