Alert archive / Missouri / Special Weather Statements in 2021

Special Weather Statement, NWS Kansas City, MO

August 20, 2021Buchanan County, Platte County, Missouri; Atchison County, Leavenworth County, Kansas

NWS Kansas City, MO issued this special weather statement at Aug 20, 2021, 9:13 PM CDT for Buchanan County, Platte County, Missouri; Atchison County, Leavenworth County, Kansas. It was in force for 47 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 20, 2021, 9:13 PM CDT (02:13 UTC)
Expired: Aug 20, 2021, 10:00 PM CDT
In force: 47 min
Issued by: NWS Kansas City, MO
Hail: 0.75 in
Wind: 50

Counties Atchison County, KS, Leavenworth County, KS, Buchanan County, MO, Platte County, MO

The radar

The Topeka radar (KTWX), 102 km from the middle of the area, began a volume at 02:12 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

Topeka, KS (KTOP), launched 00:00Z, 2.2 hours before the alert went out and 63 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: 3676 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 1017 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 145 m²/s²
0-3 km storm-relative helicity: 242 m²/s²
Significant tornado parameter: 3.1
Supercell composite: 18.5

Open this sounding in Storm Lab

The text

As transmitted.

762 
WWUS83 KEAX 210213
SPSEAX

Special Weather Statement
National Weather Service Kansas City/Pleasant Hill MO
913 PM CDT Fri Aug 20 2021
 
KSZ025-102-103-MOZ020-028-210300-
Doniphan KS-Atchison KS-Leavenworth KS-Platte MO-Buchanan MO-
913 PM CDT Fri Aug 20 2021

...Strong thunderstorms will impact portions of southern Doniphan,
Leavenworth, Atchison, Buchanan and western Platte Counties through
1000 PM CDT...

At 913 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Denton to near Nortonville to near Valley
Falls. Movement was east at 30 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

Locations impacted include...
St. Joseph, Leavenworth, Lansing, Atchison, Platte City, Weston,
Wathena, Elwood, Troy, Agency, Effingham, Dearborn, Camden Point,
Rushville, Lancaster, Easton, Tracy, Denton, Lewis And Clark Village
and Doniphan.

This includes the following highways...
 Interstate 29 between mile markers 16 and 48.
 Interstate 435 between mile markers 25 and 32.
 Interstate 229 between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
northeastern Kansas...and northwestern and west central Missouri.

&&

LAT...LON 3945 9548 3965 9544 3965 9534 3978 9534
      3979 9471 3927 9472 3913 9508 3915 9518
      3942 9518 3942 9551
TIME...MOT...LOC 0213Z 274DEG 25KT 3973 9525 3947 9527 3931 9547 

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

$$

Leighton

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 7:39 PM CDT	Severe Thunderstorm Warning	EAX	Atchison, Holt, Nodaway	51 min
Aug 20, 8:10 PM CDT	Severe Thunderstorm Warning	EAX	Holt	20 min
Aug 20, 8:29 PM CDT	Special Weather Statement	EAX	Andrew, Buchanan, Holt	31 min
Aug 20, 8:31 PM CDT	Severe Thunderstorm Warning	EAX	Andrew, Buchanan, Clinton, DeKalb, Gentry, Holt and 1 more	44 min
Aug 20, 9:41 PM CDT	Special Weather Statement	EAX	Buchanan, Caldwell, Clay, Clinton, Platte	49 min
Aug 20, 10:11 PM CDT	Special Weather Statement	EAX	Clay, Jackson, Ray	49 min
Aug 20, 10:44 PM CDT	Severe Thunderstorm Warning	EAX	Cass, Clay, Jackson, Platte	46 min
Aug 20, 11:18 PM CDT	Special Weather Statement	EAX	Bates, Cass, Johnson	42 min
Aug 20, 11:39 PM CDT	Special Weather Statement	EAX	Cooper, Howard, Pettis, Saline	51 min
Aug 21, 12:02 AM CDT	Special Weather Statement	EAX	Henry, Pettis	28 min
Aug 20, 10:29 PM CDT	Special Weather Statement	EAX	Atchison	46 min

Nearby

Special Weather Statements in Missouri, 2021 Special Weather Statements in Kansas, 2021 Every special weather statement 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.