Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 7, NWS Riverton, WY

July 9, 2021Johnson County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 9, 2021, 6:35 PM MDT for Johnson County, Wyoming. It was in force for 25 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: Jul 9, 2021, 6:35 PM MDT (00:35 UTC)
Expired: Jul 9, 2021, 7:00 PM MDT
In force: 25 min
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Johnson County, WY

The radar

The Riverton/Lander radar (KRIW), 236 km from the middle of the area, began a volume at 00:36 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

Riverton, WY (KRIW), launched 00:00Z, 0.6 hours before the alert went out and 231 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: 4123 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

163 
WUUS55 KRIW 100035
SVRRIW
WYC019-100100-
/O.NEW.KRIW.SV.W.0007.210710T0035Z-210710T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Riverton WY
635 PM MDT Fri Jul 9 2021

The National Weather Service in Riverton has issued a

* Severe Thunderstorm Warning for...
  Northeastern Johnson County in north central Wyoming...

* Until 700 PM MDT.

* At 634 PM MDT, a severe thunderstorm was located 20 miles east of
  Lake De Smet, or 23 miles northeast of Buffalo, moving southeast at
  60 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.

* This severe thunderstorm will remain over mainly rural areas of
  northeastern Johnson County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4456 10656 4456 10601 4424 10602
TIME...MOT...LOC 0034Z 301DEG 53KT 4457 10636 

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

VandenBoogart

2 follow-up statements

799 
WWUS55 KRIW 100048
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
648 PM MDT Fri Jul 9 2021

WYC019-100100-
/O.CON.KRIW.SV.W.0007.000000T0000Z-210710T0100Z/
Johnson-
648 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM MDT
FOR NORTHEASTERN JOHNSON COUNTY...

At 647 PM MDT, a severe thunderstorm was located 12 miles west of
Echeta, or 30 miles east of Buffalo, moving southeast at 60 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of
northeastern Johnson County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4456 10656 4456 10601 4424 10602
TIME...MOT...LOC 0047Z 301DEG 53KT 4446 10611 

HAIL...0.88IN
WIND...60MPH
 
$$

VandenBoogart

920 
WWUS55 KRIW 100057
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
657 PM MDT Fri Jul 9 2021

WYC019-100105-
/O.EXP.KRIW.SV.W.0007.000000T0000Z-210710T0100Z/
Johnson-
657 PM MDT Fri Jul 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN JOHNSON COUNTY
WILL EXPIRE AT 700 PM MDT...
                
The storm which prompted the warning has likely weakened below 
severe limits, and no longer poses an immediate threat to life or 
property. Therefore, the warning will be allowed to expire at 700 pm 
MDT. However gusty winds are still possible over then next 30 
minutes in association with this thunderstorm.

LAT...LON 4456 10656 4456 10601 4424 10602
TIME...MOT...LOC 0055Z 301DEG 53KT 4443 10604 

$$

VandenBoogart

Nearby

Severe Thunderstorm Warnings in Wyoming, 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.