Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 8, NWS Riverton, WY

July 13, 2021Natrona County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 13, 2021, 7:06 PM MDT for Natrona County, Wyoming. It was in force for 24 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 13, 2021, 7:06 PM MDT (01:06 UTC)
Expired: Jul 13, 2021, 7:30 PM MDT
In force: 24 min
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

County Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 179 km from the middle of the area, began a volume at 01:09 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 13, 4:25 PM MDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 1.1 hours before the alert went out and 173 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: 478 J/kg
Mixed-layer CIN: -130 J/kg
Mixed-layer LCL: 3004 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 167 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

039 
WUUS55 KRIW 140106
SVRRIW
WYC025-140130-
/O.NEW.KRIW.SV.W.0008.210714T0106Z-210714T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Riverton WY
706 PM MDT Tue Jul 13 2021

The National Weather Service in Riverton has issued a

* Severe Thunderstorm Warning for...
  Northeastern Natrona County in central Wyoming...

* Until 730 PM MDT.

* At 706 PM MDT, a severe thunderstorm was located near Teapot Rock,
  or 30 miles southeast of Kaycee, moving east at 55 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 Natrona County.

This includes Interstate 25 between mile markers 209 and 229.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

&&

LAT...LON 4316 10646 4342 10657 4349 10608 4323 10607
      4309 10608
TIME...MOT...LOC 0106Z 280DEG 49KT 4332 10633 

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

Fisher

1 follow-up statement

491 
WWUS55 KRIW 140125
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
725 PM MDT Tue Jul 13 2021

WYC025-140135-
/O.EXP.KRIW.SV.W.0008.000000T0000Z-210714T0130Z/
Natrona-
725 PM MDT Tue Jul 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN NATRONA COUNTY
WILL EXPIRE AT 730 PM MDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds are still possible with
this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
central Wyoming.

LAT...LON 4316 10646 4342 10657 4349 10608 4323 10607
      4309 10608
TIME...MOT...LOC 0125Z 280DEG 49KT 4328 10600 

$$

Fisher

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 13, 6:00 PM MDT	Special Weather Statement	RIW	Natrona	30 min
Jul 13, 6:10 PM MDT	Special Weather Statement	RIW	Natrona	35 min
Jul 13, 6:14 PM MDT	Special Weather Statement	RIW	Natrona	31 min
Jul 13, 6:21 PM MDT	Special Weather Statement	RIW	Park	24 min
Jul 13, 6:46 PM MDT	Special Weather Statement	RIW	Natrona	44 min
Jul 13, 6:53 PM MDT	Special Weather Statement	RIW	Big Horn	37 min
Jul 13, 7:28 PM MDT	Special Weather Statement	RIW	Big Horn	32 min
Jul 14, 12:01 AM MDT	Special Weather Statement	RIW	Hot Springs	29 min

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.