Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 120, NWS Kansas City, MO

August 12, 2021Cass County, Jackson County, Missouri; Johnson County, Kansas

NWS Kansas City, MO issued this severe thunderstorm warning at Aug 12, 2021, 9:52 PM CDT for Cass County, Jackson County, Missouri; Johnson County, Kansas. It was in force for 23 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 12, 2021, 9:52 PM CDT (02:52 UTC)
Expired: Aug 12, 2021, 10:15 PM CDT
In force: 23 min
Issued by: NWS Kansas City, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Johnson County, KS, Cass County, MO, Jackson County, MO

The radar

The Pleasant Hill radar (KEAX), 38 km from the middle of the area, began a volume at 02:53 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.

Issued	Product	Office	Lasted
Aug 12, 5:19 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 2.9 hours before the alert went out and 84 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: 4214 J/kg
Mixed-layer CIN: -86 J/kg
Mixed-layer LCL: 1420 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 110 m²/s²
0-3 km storm-relative helicity: 179 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.4

Open this sounding in Storm Lab

The text

As transmitted.

970 
WUUS53 KEAX 130252
SVREAX
KSC091-MOC037-095-130315-
/O.NEW.KEAX.SV.W.0120.210813T0252Z-210813T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Kansas City/Pleasant Hill MO
952 PM CDT Thu Aug 12 2021

The National Weather Service in Pleasant Hill has issued a

* Severe Thunderstorm Warning for...
  Southeastern Johnson County in east central Kansas...
  Northwestern Cass County in west central Missouri...
  Southwestern Jackson County in west central Missouri...

* Until 1015 PM CDT.

* At 952 PM CDT, a severe thunderstorm was located over Olathe,
  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...
  Overland Park, Olathe, Leawood, Grandview, Belton, Gardner, Spring
  Hill, Stanley, Clare and Stillwell.

This includes Interstate 35 in Kansas between mile markers 210 and
220.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3892 9489 3892 9451 3872 9452 3873 9461
      3874 9461 3873 9466 3876 9490
TIME...MOT...LOC 0252Z 271DEG 21KT 3886 9478 

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

$$

HB

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 8:01 PM CDT	Special Weather Statement	EAX	Jackson	29 min
Aug 12, 8:16 PM CDT	Severe Thunderstorm Warning	EAX	Jackson	29 min
Aug 12, 8:45 PM CDT	Special Weather Statement	EAX	Jackson	30 min
Aug 12, 8:53 PM CDT	Severe Thunderstorm Warning	EAX	Jackson, Johnson, Lafayette, Ray	15 min
Aug 12, 9:06 PM CDT	Severe Thunderstorm Warning	EAX	Cass, Jackson	24 min
Aug 12, 9:29 PM CDT	Severe Thunderstorm Warning	EAX	Cass, Jackson	31 min
Aug 12, 11:39 PM CDT	River Flood Warning	EAX	Jackson	8 hr
Aug 12, 11:39 PM CDT	River Flood Warning	EAX	Jackson	18 hr
Aug 12, 11:52 PM CDT	Special Weather Statement	EAX	Bates	23 min
Aug 12, 11:57 PM CDT	Severe Thunderstorm Warning	EAX	Bates	33 min
Aug 13, 5:49 AM CDT	Areal Flood Warning	EAX	Bates, Cass, Henry	12 hr
Aug 13, 9:59 AM CDT	River Flood Warning	EAX	Bates, Cass, Henry	12 hr
Aug 12, 7:32 PM CDT	Special Weather Statement	EAX	Wyandotte	28 min
Aug 12, 8:03 PM CDT	Special Weather Statement	EAX	Johnson, Wyandotte	27 min
Aug 12, 9:36 PM CDT	Severe Thunderstorm Warning	EAX	Johnson, Leavenworth, Wyandotte	24 min
Aug 12, 9:55 PM CDT	Severe Thunderstorm Warning	EAX	Johnson, Leavenworth, Wyandotte	20 min
Aug 12, 10:03 PM CDT	Flash Flood Warning	EAX	Johnson	4 hr
Aug 12, 10:16 PM CDT	Special Weather Statement	EAX	Johnson	29 min
Aug 12, 11:39 PM CDT	River Flood Warning	EAX	Johnson	4 hr
Aug 13, 12:42 AM CDT	Special Weather Statement	EAX	Atchison	33 min
Aug 13, 1:57 AM CDT	Flash Flood Warning	EAX	Johnson, Leavenworth, Wyandotte	6 hr
Aug 13, 7:39 AM CDT	Areal Flood Warning	EAX	Johnson, Leavenworth, Wyandotte	10 hr

Nearby

Severe Thunderstorm Warnings in Missouri, 2021 Severe Thunderstorm Warnings in Kansas, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.