Alert archive / Missouri / Tornado Warnings in 2020

Tornado Warning 11, NWS St. Louis, MO

August 31, 20204 counties in Missouri

NWS St. Louis, MO issued this tornado warning at Aug 31, 2020, 11:08 AM CDT for 4 counties in Missouri. It was in force for 37 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
Aug 31, 2020, 11:08 AM CDT (16:08 UTC)
Expired
Aug 31, 2020, 11:45 AM CDT
In force
37 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Callaway County, MO, Gasconade County, MO, Montgomery County, MO, Osage County, MO

The radar

The St Louis radar (KLSX), 88 km from the middle of the area, began a volume at 16:08 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
Aug 31, 10:50 AM CDTSevere Thunderstorm WatchSPC3 hr

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 4.1 hours before the alert went out and 265 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, Springfield, MO at 12:00Z on 2020-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2773 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, Springfield, MO at 12:00Z on 2020-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 156 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
2773 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
710 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
156 m²/s²
0-3 km storm-relative helicity
184 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.9

Open this sounding in Storm Lab

The text

As transmitted.

491 
WFUS53 KLSX 311608
TORLSX
MOC027-073-139-151-311700-
/O.NEW.KLSX.TO.W.0011.200831T1608Z-200831T1700Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service St Louis MO
1108 AM CDT Mon Aug 31 2020

The National Weather Service in St Louis has issued a

* Tornado Warning for...
  Southwestern Montgomery County in east central Missouri...
  Southeastern Callaway County in central Missouri...
  Northeastern Osage County in central Missouri...
  Northern Gasconade County in east central Missouri...

* Until noon CDT.
    
* At 1108 AM CDT, a severe thunderstorm capable of producing a
  tornado was located near Chamois, moving east at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Swiss around 1140 AM CDT.
  Hermann around 1145 AM CDT.

Other locations impacted by this tornadic thunderstorm include
Gasconade, Portland, Morrison, Frankenstein, Bay, Steedman and
Rhineland.

This also includes Deutschheim Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3854 9191 3876 9183 3870 9137 3843 9139
TIME...MOT...LOC 1608Z 274DEG 28KT 3863 9178 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Glass
3 follow-up statements
524 
WWUS53 KLSX 311616
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1116 AM CDT Mon Aug 31 2020

MOC027-073-139-151-311700-
/O.CON.KLSX.TO.W.0011.000000T0000Z-200831T1700Z/
Montgomery MO-Callaway MO-Osage MO-Gasconade MO-
1116 AM CDT Mon Aug 31 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL NOON CDT FOR
SOUTHWESTERN MONTGOMERY...EAST CENTRAL CALLAWAY...NORTHEASTERN OSAGE
AND NORTHERN GASCONADE COUNTIES...
    
At 1115 AM CDT, a severe thunderstorm capable of producing a tornado
was located near Chamois, moving east at 30 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This dangerous storm will be near...
  Swiss around 1140 AM CDT.
  Hermann around 1145 AM CDT.

Other locations impacted by this tornadic thunderstorm include
Gasconade, Bay, Portland and Morrison.

This also includes Deutschheim Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3852 9181 3874 9179 3870 9137 3843 9139
TIME...MOT...LOC 1615Z 274DEG 28KT 3863 9170 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Glass
289 
WWUS53 KLSX 311638
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1138 AM CDT Mon Aug 31 2020

MOC027-139-311647-
/O.CAN.KLSX.TO.W.0011.000000T0000Z-200831T1700Z/
Montgomery MO-Callaway MO-
1138 AM CDT Mon Aug 31 2020

...THE TORNADO WARNING FOR SOUTHWESTERN MONTGOMERY AND EAST CENTRAL
CALLAWAY COUNTIES IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 200 PM CDT for
east central Missouri.

LAT...LON 3870 9172 3869 9159 3868 9156 3868 9154
      3866 9137 3843 9139 3850 9170 3857 9176
TIME...MOT...LOC 1637Z 274DEG 28KT 3862 9148 

$$

MOC073-151-311700-
/O.CON.KLSX.TO.W.0011.000000T0000Z-200831T1700Z/
Osage MO-Gasconade MO-
1138 AM CDT Mon Aug 31 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL NOON CDT FOR
NORTHEASTERN OSAGE AND NORTHERN GASCONADE COUNTIES...
    
At 1137 AM CDT, a severe thunderstorm capable of producing a tornado
was located near Swiss, moving east at 30 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This tornadic thunderstorm will remain over mainly rural areas of
northeastern Osage and northern Gasconade Counties, including the
following locations... Gasconade, Morrison and Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3870 9172 3869 9159 3868 9156 3868 9154
      3866 9137 3843 9139 3850 9170 3857 9176
TIME...MOT...LOC 1637Z 274DEG 28KT 3862 9148 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Glass
496 
WWUS53 KLSX 311645
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1145 AM CDT Mon Aug 31 2020

MOC073-151-311654-
/O.CAN.KLSX.TO.W.0011.000000T0000Z-200831T1700Z/
Osage MO-Gasconade MO-
1145 AM CDT Mon Aug 31 2020

...THE TORNADO WARNING FOR NORTHEASTERN OSAGE AND NORTHERN GASCONADE
COUNTIES IS CANCELLED...
    
The tornado threat has diminished and the Tornado Warning has been 
cancelled. However, damaging winds remain likely and a Severe 
Thunderstorm Warning remains in effect for parts of the area.

A Severe Thunderstorm Watch remains in effect until 200 PM CDT for
east central Missouri.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
St Louis.


LAT...LON 3870 9172 3869 9159 3868 9156 3868 9154
      3866 9137 3843 9139 3850 9170 3857 9176
TIME...MOT...LOC 1641Z 274DEG 28KT 3862 9141 

$$

Glass

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 10:01 AM CDTSevere Thunderstorm WarningLSXBoone, Cole, Moniteau44 min
Aug 31, 10:35 AM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Cole, Osage40 min
Aug 31, 10:59 AM CDTSevere Thunderstorm WarningLSXCallaway, Franklin, Gasconade, Montgomery, Osage, Warren46 min
Aug 31, 11:41 AM CDTSevere Thunderstorm WarningLSXCrawford, Franklin, Gasconade49 min
Aug 31, 12:17 PM CDTSevere Thunderstorm WarningLSXCrawford, Washington43 min

Nearby

Tornado Warnings in Missouri, 2020Every tornado warning in 2020Tornadoes in 2020

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.