Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 135, NWS Kansas City, MO

September 20, 2021Clay County, Jackson County, Missouri

NWS Kansas City, MO issued this severe thunderstorm warning at Sep 20, 2021, 6:00 PM CDT for Clay County, Jackson County, Missouri. It was in force for 45 min. 1 report 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: Sep 20, 2021, 6:00 PM CDT (23:00 UTC)
Expired: Sep 20, 2021, 6:45 PM CDT
In force: 45 min
Issued by: NWS Kansas City, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Clay County, MO, Jackson County, MO

The radar

The Pleasant Hill radar (KEAX), 40 km from the middle of the area, began a volume at 23:00 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
Sep 20, 6:17 PM CDT	HAIL 0.75	4 E Independence, MO	DELAYED REPORT FROM MPING.

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
Sep 20, 3:25 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 11.0 hours before the alert went out and 117 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: 583 J/kg
Mixed-layer CIN: -288 J/kg
Mixed-layer LCL: 1142 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 185 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

850 
WUUS53 KEAX 202300
SVREAX
MOC047-095-202345-
/O.NEW.KEAX.SV.W.0135.210920T2300Z-210920T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Kansas City/Pleasant Hill MO
600 PM CDT Mon Sep 20 2021

The National Weather Service in Pleasant Hill has issued a

* Severe Thunderstorm Warning for...
  Southeastern Clay County in west central Missouri...
  Northern Jackson County in west central Missouri...

* Until 645 PM CDT.

* At 559 PM CDT, a severe thunderstorm was located near Raytown,
  moving northeast 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...
  Kansas City, Independence, Lee's Summit, Blue Springs, Raytown,
  Sugar Creek, Buckner, Courtney, Lake Tapawingo, Sibley and River
  Bend.

This includes the following highways...
 Interstate 70 in Missouri between mile markers 7 and 21.
 Interstate 470 near mile marker 16.
 Interstate 435 between mile markers 58 and 63.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3920 9438 3926 9422 3924 9421 3921 9421
      3921 9420 3904 9412 3901 9449 3911 9452
TIME...MOT...LOC 2259Z 246DEG 22KT 3904 9446 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Klaus

2 follow-up statements

759 
WWUS53 KEAX 202317
SVSEAX

Severe Weather Statement
National Weather Service Kansas City/Pleasant Hill MO
617 PM CDT Mon Sep 20 2021

MOC047-095-202345-
/O.CON.KEAX.SV.W.0135.000000T0000Z-210920T2345Z/
Clay MO-Jackson MO-
617 PM CDT Mon Sep 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR SOUTHEASTERN CLAY AND NORTHEASTERN JACKSON COUNTIES...

At 616 PM CDT, a severe thunderstorm was located over Independence,
moving northeast 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...
Independence, Blue Springs, Sugar Creek, Buckner, Courtney, Lake
Tapawingo, Sibley and River Bend.

This includes the following highways...
 Interstate 70 in Missouri between mile markers 15 and 21.
 Interstate 470 near mile marker 16.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3920 9438 3926 9422 3924 9421 3921 9421
      3921 9420 3904 9412 3902 9436 3917 9442
TIME...MOT...LOC 2316Z 246DEG 22KT 3908 9433 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Klaus

412 
WWUS53 KEAX 202340
SVSEAX

Severe Weather Statement
National Weather Service Kansas City/Pleasant Hill MO
640 PM CDT Mon Sep 20 2021

MOC047-095-202348-
/O.EXP.KEAX.SV.W.0135.000000T0000Z-210920T2345Z/
Clay MO-Jackson MO-
640 PM CDT Mon Sep 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CLAY AND
NORTHEASTERN JACKSON COUNTIES WILL EXPIRE AT 645 PM CDT...
        
The storm which prompted the warning in northern Jackson County has 
weakened below severe limits, and has exited the warned area. 
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 1000 PM CDT for
west central Missouri.

Remember, a Severe Thunderstorm Warning still remains in effect for
eastern Clay and Ray counties.

LAT...LON 3920 9438 3926 9422 3924 9421 3921 9421
      3921 9420 3904 9412 3902 9436 3917 9442
TIME...MOT...LOC 2338Z 246DEG 22KT 3913 9417 

$$

Klaus

The office that day

Everything else NWS Kansas City, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 20, 4:00 PM CDT	Special Weather Statement	EAX	Buchanan	30 min
Sep 20, 4:12 PM CDT	Severe Thunderstorm Warning	EAX	Harrison, Worth	33 min
Sep 20, 4:36 PM CDT	Special Weather Statement	EAX	DeKalb	24 min
Sep 20, 4:57 PM CDT	Severe Thunderstorm Warning	EAX	Daviess, DeKalb, Gentry, Harrison	33 min
Sep 20, 5:13 PM CDT	Severe Thunderstorm Warning	EAX	Clay, Clinton, Platte	47 min
Sep 20, 5:29 PM CDT	Severe Thunderstorm Warning Considerable damage threat	EAX	Jackson	46 min
Sep 20, 5:33 PM CDT	Severe Thunderstorm Warning	EAX	Clay, Clinton, Platte	42 min
Sep 20, 5:49 PM CDT	Special Weather Statement	EAX	Daviess	26 min
Sep 20, 6:13 PM CDT	Severe Thunderstorm Warning	EAX	Bates	47 min
Sep 20, 6:23 PM CDT	Severe Thunderstorm Warning	EAX	Clay, Jackson, Ray	52 min
Sep 20, 6:34 PM CDT	Special Weather Statement	EAX	Cass	26 min
Sep 20, 6:47 PM CDT	Severe Thunderstorm Warning	EAX	Carroll, Lafayette, Ray	43 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.