Alert archive / Wyoming / Snow Squall Warnings in 2021

Snow Squall Warning 3, NWS Cheyenne, WY

January 5, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this snow squall warning at Jan 5, 2021, 5:17 PM MST for Laramie County, Wyoming. It was in force for 43 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, 5:17 PM MST (00:17 UTC)
Expired
Jan 5, 2021, 6:00 PM MST
In force
43 min
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 11 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.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.3 hours before the alert went out and 201 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2021-01-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2021-01-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2321 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
9 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.

528 
WWUS55 KCYS 060018
SQWCYS

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

WYC021-060100-
/O.NEW.KCYS.SQ.W.0003.210106T0017Z-210106T0100Z/
Laramie WY-
517 PM MST Tue Jan 5 2021

The National Weather Service in Cheyenne has issued a

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

* Until 600 PM MST.

* At 517 PM MST, a dangerous snow squall was located over Warren AFB,
  or near Cheyenne, moving south at 15 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 10.
 Interstate 80 in Wyoming between mile markers 345 and 361.

Locations impacted include...
Cheyenne, South Greeley, Warren Af Base, Warren AFB, South Greeley
High and Fox Farm-College.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4131 10505 4102 10470 4100 10470 4100 10517
TIME...MOT...LOC 0017Z 352DEG 11KT 4112 10490 

$$

Wilkinson/Braun
1 follow-up statement
863 
WWUS55 KCYS 060051
SQWCYS

Snow Squall Warning
National Weather Service Cheyenne WY
550 PM MST Tue Jan 5 2021

WYC021-060100-
/O.EXP.KCYS.SQ.W.0003.000000T0000Z-210106T0100Z/
Laramie WY-
550 PM MST Tue Jan 5 2021

...THE SNOW SQUALL WARNING FOR SOUTHWESTERN LARAMIE COUNTY WILL
EXPIRE AT 600 PM MST...

The snow squall which prompted the warning has weakened and exited
the area. Therefore, the snow squall warning will be allowed to
expire. Areas of blowing snow and snow-covered roads will continue to
make travel difficult early this evening.

LAT...LON 4131 10505 4102 10470 4100 10470 4100 10517
TIME...MOT...LOC 0050Z 352DEG 11KT 4105 10489 

$$

Wilkinson/Brothers

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 6, 4:37 AM MSTHigh Wind WarningCYSAlbany, Carbon6 hr

Nearby

Snow Squall Warnings in Wyoming, 2021Every 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.