Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 51, NWS St. Louis, MO

May 27, 2021Franklin County, Saint Louis County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at May 27, 2021, 1:09 PM CDT for Franklin County, Saint Louis County, Missouri. It was in force for 51 min. 2 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: May 27, 2021, 1:09 PM CDT (18:09 UTC)
Expired: May 27, 2021, 2:00 PM CDT
In force: 51 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Franklin County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 20 km from the middle of the area, began a volume at 18:09 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

Time	Report	Where	Remark
May 27, 1:09 PM CDT	TSTM WND GST 60	3 S Matson, MO	ALSO, PENNY SIZED HAIL.
May 27, 1:15 PM CDT	HAIL 0.7	1 Wsw Gray Summit, MO

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.

Issued	Product	Office	Lasted
May 27, 11:26 AM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 6.2 hours before the alert went out and 253 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1679 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 130 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

982 
WUUS53 KLSX 271809
SVRLSX
MOC071-189-271900-
/O.NEW.KLSX.SV.W.0051.210527T1809Z-210527T1900Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
109 PM CDT Thu May 27 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northeastern Franklin County in east central Missouri...
  Southwestern St. Louis County in east central Missouri...

* Until 200 PM CDT.

* At 109 PM CDT, a severe thunderstorm was located over Gray Summit,
  moving east at 25 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Eureka, Ballwin, Ellisville, Clarkson Valley, Winchester, 
  Manchester, Twin Oaks, Valley Park, Murphy, Des Peres, Fenton and 
  Sunset Hills.

This includes Interstate 44 in Missouri between exits 253 and 274.
 
This also includes Route 66 State Park and Castlewood State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3850 9042 3850 9059 3849 9063 3848 9073
      3846 9084 3856 9087 3857 9085 3865 9050
TIME...MOT...LOC 1809Z 262DEG 23KT 3852 9078 

HAIL...1.00IN
WIND...60MPH
 
$$

Carney

2 follow-up statements

484 
WWUS53 KLSX 271834
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
134 PM CDT Thu May 27 2021

MOC071-189-271900-
/O.CON.KLSX.SV.W.0051.000000T0000Z-210527T1900Z/
Franklin MO-St. Louis MO-
134 PM CDT Thu May 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM CDT
FOR NORTHEASTERN FRANKLIN AND SOUTHWESTERN ST. LOUIS COUNTIES...

At 133 PM CDT, a severe thunderstorm was located over Pacific, moving
east at 25 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Chesterfield, Wildwood, Ballwin, Manchester, Town and Country,
Eureka, Ellisville, Sunset Hills, Des Peres, Pacific, Valley Park,
Fenton, Clarkson Valley, Gray Summit, Murphy, Winchester, Twin Oaks
and Peerless Park.

This also includes Route 66 State Park and Castlewood State Park.
 
This includes Interstate 44 in Missouri between exits 253 and 274.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3850 9042 3850 9059 3849 9063 3848 9073
      3846 9084 3856 9087 3857 9085 3865 9050
TIME...MOT...LOC 1833Z 253DEG 20KT 3850 9075 

HAIL...1.00IN
WIND...60MPH
 
$$

Carney

786 
WWUS53 KLSX 271853
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
153 PM CDT Thu May 27 2021

MOC071-189-271902-
/O.EXP.KLSX.SV.W.0051.000000T0000Z-210527T1900Z/
Franklin MO-St. Louis MO-
153 PM CDT Thu May 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN FRANKLIN AND
SOUTHWESTERN ST. LOUIS COUNTIES WILL EXPIRE AT 200 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
east central Missouri.

LAT...LON 3850 9042 3850 9059 3849 9063 3848 9073
      3846 9084 3856 9087 3857 9085 3865 9050
TIME...MOT...LOC 1852Z 262DEG 23KT 3852 9061 

$$

Carney

The office that day

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

Issued	Product	Office	Counties	Lasted
May 27, 11:13 AM CDT	Severe Thunderstorm Warning	LSX	Lincoln, Saint Charles, Warren	47 min
May 27, 11:50 AM CDT	Severe Thunderstorm Warning	LSX	Franklin, Lincoln, Saint Charles, Saint Louis, Warren, City of Saint Louis	55 min
May 27, 12:39 PM CDT	Areal Flood Advisory	LSX	Franklin, Jefferson, Saint Charles, Saint Louis, City of Saint Louis	3 hr
May 27, 1:24 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Gasconade	51 min
May 27, 1:51 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Franklin, Washington	39 min
May 27, 2:46 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Sainte Genevieve	29 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2021 Every severe thunderstorm warning in 2021

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.