Alert archive / Missouri / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 474, NWS St. Louis, MO

July 29, 2011Knox County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 29, 2011, 2:48 AM CDT for Knox County, Missouri. It was in force for 42 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
Jul 29, 2011, 2:48 AM CDT (07:48 UTC)
Expired
Jul 29, 2011, 3:30 AM CDT
In force
42 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Knox County, MO

The radar

The Quad Cities radar (KDVN), 202 km from the middle of the area, began a volume at 07:49 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 7.8 hours before the alert went out and 207 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 2011-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4421 joules per kilogram.LCLEL10008507005003002001001 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, Davenport, at 00:00Z on 2011-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 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
4421 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
764 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
121 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.8

Open this sounding in Storm Lab

The text

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

970 
WUUS53 KLSX 290748
SVRLSX
MOC103-290830-
/O.NEW.KLSX.SV.W.0474.110729T0748Z-110729T0830Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
248 AM CDT FRI JUL 29 2011

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

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

* UNTIL 330 AM CDT

* AT 246 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED 5 MILES NORTH OF BRASHEAR...OR 9
  MILES EAST OF KIRKSVILLE...AND MOVING NORTHEAST AT 10 MPH. PENNY
  SIZE HAIL MAY ALSO ACCOMPANY THESE DAMAGING WINDS.

* LOCATIONS IMPACTED INCLUDE...
  EDINA...GREENSBURG...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 9195 4030 9195 4023 9195 4002 9234
      4004 9235 4025 9236 4031 9234 4031 9211
TIME...MOT...LOC 0747Z 228DEG 9KT 4022 9241
WIND...HAIL 60MPH 0.75IN

$$

BYRD
2 follow-up statements
997 
WWUS53 KLSX 290810
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
310 AM CDT FRI JUL 29 2011

MOC103-290830-
/O.CON.KLSX.SV.W.0474.000000T0000Z-110729T0830Z/
KNOX MO-
310 AM CDT FRI JUL 29 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHERN KNOX
COUNTY UNTIL 330 AM CDT...

AT 304 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF
60 MPH.  THIS STORM WAS LOCATED 6 MILES NORTH OF BRASHEAR...OR 11
MILES EAST OF KIRKSVILLE...MOVING NORTHEAST AT 10 MPH. PENNY SIZE 
HAIL MAY ALSO ACCOMPANY THESE DAMAGING WINDS. ANOTHER SEVERE STORM 
WAS OVER GREENSBURG AND MOVING NORTHEAST AT 10 MPH.

LOCATIONS IMPACTED INCLUDE...
  BARING AND GREENSBURG.

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 9195 4030 9195 4023 9195 4002 9234
      4004 9235 4025 9236 4031 9234 4031 9211
TIME...MOT...LOC 0808Z 228DEG 9KT 4025 9236
WIND...HAIL 60MPH 0.75IN

$$

BYRD
526 
WWUS53 KLSX 290828
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
328 AM CDT FRI JUL 29 2011

MOC103-290838-
/O.EXP.KLSX.SV.W.0474.000000T0000Z-110729T0830Z/
KNOX MO-
328 AM CDT FRI JUL 29 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN KNOX COUNTY WILL
EXPIRE AT 330 AM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED.  HOWEVER SMALL 
HAIL...GUSTY WINDS TO 40 MPH AND HEAVY RAIN ARE STILL POSSIBLE WITH 
THIS THUNDERSTORM.

LAT...LON 4031 9195 4030 9195 4023 9195 4002 9234
      4004 9235 4025 9236 4031 9234 4031 9211
TIME...MOT...LOC 0828Z 228DEG 9KT 4028 9231

$$

BYRD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 9:26 PM CDTRiver Flood WarningLSXPerry, Sainte Genevieve10 days
Jul 28, 10:51 PM CDTSevere Thunderstorm WarningLSXLewis, Marion, Shelby39 min
Jul 28, 11:14 PM CDTSevere Thunderstorm WarningLSXLewis33 min
Jul 29, 3:00 AM CDTExcessive Heat WatchLSXAudrain, Knox, Lewis, Marion, Monroe, Pike and 2 more37 hr
Jul 29, 5:55 PM CDTSevere Thunderstorm WarningLSXIron, Reynolds35 min

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.