Alert archive / Wyoming / Snow Squall Warnings in 2021

Snow Squall Warning 14, NWS Cheyenne, WY

February 20, 2021Albany County, Laramie County, Wyoming

NWS Cheyenne, WY issued this snow squall warning at Feb 20, 2021, 3:30 PM MST for Albany County, Laramie County, Wyoming. It was in force for 30 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: Feb 20, 2021, 3:30 PM MST (22:30 UTC)
Expired: Feb 20, 2021, 4:00 PM MST
In force: 30 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon

Counties Albany County, WY, Laramie County, WY

The radar

The Cheyenne radar (KCYS), 43 km from the middle of the area, began a volume at 22:36 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

Denver, CO (KDNR), launched 12:00Z, 10.5 hours before the alert went out and 228 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: 2205 m above ground
0-6 km bulk shear: 75 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 183 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

975 
WWUS55 KCYS 202231
SQWCYS

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service Cheyenne WY
330 PM MST Sat Feb 20 2021

WYC001-021-202300-
/O.NEW.KCYS.SQ.W.0014.210220T2230Z-210220T2300Z/
Albany WY-Laramie WY-
330 PM MST Sat Feb 20 2021

The National Weather Service in Cheyenne has issued a

* Snow Squall Warning for...
  Southeastern Albany County in southeastern Wyoming...
  Southwestern Laramie County in southeastern Wyoming...

* Until 400 PM MST.

* At 330 PM MST, a dangerous snow squall was located over Yellow Pine
  Campground, or 12 miles southeast of Laramie, moving east at 20
  mph.

  HAZARD...Extremely poor visibility in snow and blowing snow. Wind 
           gusts up to 20 mph.

  SOURCE...Radar and webcams.

  IMPACT...Expect hazardous road conditions.

This includes Interstate 80 in Wyoming between mile markers 317 and
350.
 
Locations impacted include...
Tie City Campground, Granite Springs Reservoir, North Crow
Campground, Vedauwoo, Federal, Granite Springs Campground, Crystal
Lake Reservoir, Crystal Lake Campground, Vedauwoo Campground, Buford
and Yellow Pine Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Consider avoiding or delaying travel until the snow squall passes
your location. If you must travel, use extra caution and allow extra
time. Rapid changes in visibility and slick road conditions may lead
to accidents.

If traveling on a highway, find the nearest exit or rest area and
park safely away from traffic. Allow snow squalls to pass before
attempting to resume travel.

&&

LAT...LON 4120 10554 4142 10550 4121 10494 4100 10511
      4100 10530
TIME...MOT...LOC 2230Z 291DEG 19KT 4122 10537 

$$

Hammer

1 follow-up statement

511 
WWUS55 KCYS 202258
SQWCYS

Snow Squall Warning
National Weather Service Cheyenne WY
358 PM MST Sat Feb 20 2021

WYC001-021-202308-
/O.EXP.KCYS.SQ.W.0014.000000T0000Z-210220T2300Z/
Albany WY-Laramie WY-
358 PM MST Sat Feb 20 2021

...THE SNOW SQUALL WARNING FOR SOUTHEASTERN ALBANY AND SOUTHWESTERN
LARAMIE COUNTIES WILL EXPIRE AT 400 PM MST...

The snow squall which prompted the warning has weakened. Therefore,
the snow squall warning will be allowed to expire. Roads will remain
slick and hazardous due to icy conditions.

LAT...LON 4120 10554 4142 10550 4121 10494 4100 10511
      4100 10530
TIME...MOT...LOC 2258Z 291DEG 19KT 4117 10520 

$$

Hammer

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 20, 2:23 AM MST	High Wind Watch	CYS	Albany, Carbon, Laramie, Platte	11 hr
Feb 20, 1:23 PM MST	High Wind Watch	CYS	Laramie	13 hr
Feb 20, 1:23 PM MST	High Wind Warning	CYS	Albany, Carbon, Converse, Goshen, Laramie, Platte	3 days

Nearby

Snow Squall Warnings in Wyoming, 2021 Every snow squall 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.