Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 141, NWS Cheyenne, WY

September 11, 2021Albany County, Carbon County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 11, 2021, 6:22 PM MDT for Albany County, Carbon County, Wyoming. It was in force for 38 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 11, 2021, 6:22 PM MDT (00:22 UTC)
Expired: Sep 11, 2021, 7:00 PM MDT
In force: 38 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Albany County, WY, Carbon County, WY

The radar

The Cheyenne radar (KCYS), 141 km from the middle of the area, began a volume at 00:22 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 11, 6:28 PM MDT	TSTM WND GST 65	Arlington, WY	MEASURED WIND GUST OF 65 MPH FROM WYDOT MESONET ALONG I-80.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 0.4 hours before the alert went out and 227 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: 2772 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 6 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

612 
WUUS55 KCYS 120022
SVRCYS
WYC001-007-120100-
/O.NEW.KCYS.SV.W.0141.210912T0022Z-210912T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
622 PM MDT Sat Sep 11 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  East central Carbon County in south central Wyoming...
  Central Albany County in southeastern Wyoming...

* Until 700 PM MDT.

* At 620 PM MDT, a severe thunderstorm producing gusty winds of 55 
  to 65 mph was located over Arlington, or 40 miles northwest of 
  Laramie, moving northeast at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Observed wind gusts along I-80.

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

* Locations impacted include...
  Hanna, Medicine Bow, Rock River, Elk Mountain, Bow River Campground
  and Arlington.

This includes Interstate 80 in Wyoming between mile markers 246 and
280.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4146 10634 4169 10655 4180 10675 4198 10666
      4198 10630 4190 10588 4167 10562
TIME...MOT...LOC 0020Z 231DEG 27KT 4160 10626 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Allen

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 12, 3:25 PM MDT	Special Weather Statement	CYS	Laramie	35 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.