Alert archive / Wyoming / Snow Squall Warnings in 2021

Snow Squall Warning 1, NWS Cheyenne, WY

January 5, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this snow squall warning at Jan 5, 2021, 4:31 PM MST for Laramie County, Wyoming. It was in force for 44 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: Jan 5, 2021, 4:31 PM MST (23:31 UTC)
Expired: Jan 5, 2021, 5:15 PM MST
In force: 44 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 17 km from the middle of the area, began a volume at 23:34 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, 11.5 hours before the alert went out and 211 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: 2560 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 148 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

359 
WWUS55 KCYS 052332
SQWCYS

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service Cheyenne WY
431 PM MST Tue Jan 5 2021

WYC021-060015-
/O.NEW.KCYS.SQ.W.0001.210105T2331Z-210106T0015Z/
Laramie WY-
431 PM MST Tue Jan 5 2021

The National Weather Service in Cheyenne has issued a

* Snow Squall Warning for...
  Western Laramie County in southeastern Wyoming...

* Until 515 PM MST.

* At 431 PM MST, a dangerous snow squall was located over Frontier
  Park, or over Cheyenne, moving south at 30 mph.

  HAZARD...Whiteout conditions. Zero visibility in heavy snow and 
           blowing snow. Wind gusts greater than 30 mph.

  SOURCE...Radar indicated.

  IMPACT...Dangerous life-threatening travel.

* 

This includes the following highways...
 Interstate 25 in Wyoming between mile markers 1 and 31.
 Interstate 80 in Wyoming between mile markers 341 and 377.

Locations impacted include...
Cheyenne, South Greeley, Federal, Crystal Lake Reservoir, Crystal
Lake Campground, Ranchettes, Warren AFB, Frontier Park, North
Cheyenne, Whitaker, Warren Af Base, Fox Farm-College and South
Greeley High.

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.

Slow Down! Rapid changes in visibility and road conditions are
expected with this dangerous snow squall. Be alert for sudden
whiteout conditions.

&&

LAT...LON 4160 10513 4120 10451 4100 10455 4100 10523
TIME...MOT...LOC 2331Z 355DEG 24KT 4115 10482 

$$

Wilkinson/Braun

The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 4, 7:54 PM MST	Winter Weather Advisory	CYS	Albany, Carbon	21 hr
Jan 5, 4:13 PM MST	Special Weather Statement	CYS	Laramie	32 min
Jan 5, 4:55 PM MST	Snow Squall Warning	CYS	Albany, Laramie	50 min

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.