Alert archive / Missouri / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 21, NWS St. Louis, MO

April 3, 2011Knox County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 3, 2011, 8:34 PM CDT for Knox County, Missouri. It was in force for 40 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
Apr 3, 2011, 8:34 PM CDT (01:34 UTC)
Expired
Apr 3, 2011, 9:14 PM CDT
In force
40 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Knox County, MO

The radar

The Quad Cities radar (KDVN), 199 km from the middle of the area, began a volume at 01:34 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
Apr 3, 8:11 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.6 hours before the alert went out and 204 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, Davenport, at 00:00Z on 2011-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1790 joules per kilogram.LCLLFCEL10008507005003002001001 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, Davenport, at 00:00Z on 2011-04-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 119 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
1790 J/kg
Mixed-layer CIN
-85 J/kg
Mixed-layer LCL
1684 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
119 m²/s²
0-3 km storm-relative helicity
168 m²/s²
Significant tornado parameter
0.3
Supercell composite
5.9

Open this sounding in Storm Lab

The text

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

548 
WUUS53 KLSX 040134
SVRLSX
MOC103-040215-
/O.NEW.KLSX.SV.W.0021.110404T0134Z-110404T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
834 PM CDT SUN APR 3 2011

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN KNOX COUNTY IN NORTHEAST MISSOURI...

* UNTIL 915 PM CDT

* AT 832 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 12
  MILES SOUTH OF NOVINGER...OR 14 MILES SOUTHWEST OF KIRKSVILLE...AND
  MOVING EAST AT 55 MPH.

* LOCATIONS IMPACTED INCLUDE...
  EDINA...KNOX CITY...COLONY...HURDLAND AND BARING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4031 9196 4030 9195 4011 9196 4004 9235
      4026 9236 4031 9215
TIME...MOT...LOC 0134Z 254DEG 46KT 4006 9273
WIND...HAIL 60MPH 1.00IN

$$

BYRD
3 follow-up statements
662 
WWUS53 KLSX 040149
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
849 PM CDT SUN APR 3 2011

MOC103-040215-
/O.CON.KLSX.SV.W.0021.000000T0000Z-110404T0215Z/
KNOX MO-
849 PM CDT SUN APR 3 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHERN KNOX
COUNTY UNTIL 915 PM CDT...

AT 845 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE 
HAIL.  THIS STORM WAS LOCATED 6 MILES SOUTHEAST OF 
KIRKSVILLE...MOVING EAST AT 55 MPH.

LOCATIONS IMPACTED INCLUDE...
  EDINA...KNOX CITY...COLONY...HURDLAND AND BARING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF 
YOUR HOME OR BUSINESS. 

&&

LAT...LON 4031 9196 4030 9195 4011 9196 4004 9235
      4026 9236 4031 9215
TIME...MOT...LOC 0149Z 252DEG 49KT 4015 9244
WIND...HAIL <50MPH 1.00IN

$$

CVKING
491 
WWUS53 KLSX 040204
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
904 PM CDT SUN APR 3 2011

MOC103-040215-
/O.CON.KLSX.SV.W.0021.000000T0000Z-110404T0215Z/
KNOX MO-
904 PM CDT SUN APR 3 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHEASTERN
KNOX COUNTY UNTIL 915 PM CDT...

AT 901 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
STORM WAS LOCATED NEAR EDINA...MOVING NORTHEAST AT 55 MPH.

LOCATIONS IMPACTED INCLUDE...
  COLONY.

LAT...LON 4031 9196 4030 9195 4021 9195 4014 9216
      4024 9223 4031 9214
TIME...MOT...LOC 0205Z 237DEG 46KT 4023 9211
WIND...HAIL <50MPH 1.00IN

$$

CVKING
321 
WWUS53 KLSX 040214
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
914 PM CDT SUN APR 3 2011

MOC103-040225-
/O.CAN.KLSX.SV.W.0021.000000T0000Z-110404T0215Z/
KNOX MO-
914 PM CDT SUN APR 3 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN KNOX COUNTY IS
CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED.

LAT...LON 4031 9196 4030 9195 4021 9195 4014 9216
      4024 9223 4031 9214
TIME...MOT...LOC 0215Z 252DEG 49KT 4026 9200

$$

CVKING

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 3, 9:30 PM CDTSevere Thunderstorm WarningLSXLewis30 min
Apr 3, 9:33 PM CDTSevere Thunderstorm WarningLSXLewis24 min
Apr 3, 11:14 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Lewis, Marion, Monroe, Pike and 2 more46 min
Apr 3, 11:21 PM CDTSevere Thunderstorm WarningLSXBoone, Cole, Moniteau39 min
Apr 3, 11:54 PM CDTSevere Thunderstorm WarningLSXAudrain, Boone, Callaway, Cole, Montgomery, Osage35 min
Apr 4, 12:25 AM CDTSevere Thunderstorm WarningLSXBoone, Cole, Moniteau30 min
Apr 4, 3:28 AM CDTSevere Thunderstorm WarningLSXCrawford, Franklin, Gasconade32 min
Apr 4, 3:55 AM CDTSevere Thunderstorm WarningLSXFranklin, Jefferson, Saint Charles, Saint Louis35 min
Apr 4, 3:58 PM CDTFreeze WarningLSXBoone, Callaway, Cole, Crawford, Franklin, Gasconade and 12 more16 hr

Nearby

Severe Thunderstorm Warnings in Missouri, 2011Every severe thunderstorm warning 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.