Alert archive / Wyoming / Winter Storm Warnings in 2021

Winter Storm Warning 7, NWS Cheyenne, WY

February 17, 2021Albany County, Laramie County, Wyoming

NWS Cheyenne, WY issued this winter storm warning at Feb 17, 2021, 12:06 PM MST for Albany County, Laramie County, Wyoming. It was in force for 15 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 17, 2021, 12:06 PM MST (19:06 UTC)
Expired
Feb 18, 2021, 3:01 AM MST
In force
15 hr
Issued by
NWS Cheyenne, WY

Counties Albany County, WY, Laramie County, WY

The radar

The Cheyenne radar (KCYS), 50 km from the middle of the area, began a volume at 19:06 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, 7.1 hours before the alert went out and 245 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 12:00Z on 2021-02-17Temperature 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 12:00Z on 2021-02-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.1939Sfc1 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
1005 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
42 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

364 
WWUS45 KCYS 171906
WSWCYS

URGENT - WINTER WEATHER MESSAGE
National Weather Service Cheyenne WY
1206 PM MST Wed Feb 17 2021

...LOCALLY HEAVY SNOW THIS AFTERNOON AND EVENING ALONG INTERSTATE
80 BETWEEN LARAMIE AND CHEYENNE... 

WYZ116-181200-
/O.NEW.KCYS.WS.W.0007.210217T1906Z-210218T1200Z/
South Laramie Range-
Including the cities of Buford, Pumpkin Vine, and Vedauwoo
1206 PM MST Wed Feb 17 2021

...WINTER STORM WARNING IN EFFECT UNTIL 5 AM MST THURSDAY...

* WHAT...Heavy snow. Total snow accumulations of 4 to 8 inches
  expected, with locally higher amounts possible. 

* WHERE...South Laramie Range including the Interstate 80 Summit
  between Laramie and Cheyenne. 

* WHEN...Now until 5 AM MST Thursday. The heaviest snow will occur
  this afternoon and evening. 

* IMPACTS...Dangerous travel conditions due to icy, snow covered
  roads and reduced visibilities in heavy snow. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

WYZ117-181200-
/O.NEW.KCYS.WW.Y.0016.210217T1906Z-210218T1200Z/
South Laramie Range Foothills-
Including the cities of Whitaker, Federal, and Horse Creek
1206 PM MST Wed Feb 17 2021

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST THURSDAY...

* WHAT...Snow. Total snow accumulations of 3 to 6 inches expected.

* WHERE...South Laramie Range Foothills including Interstate 80 between
  Laramie and Cheyenne. 

* WHEN...Now until 5 AM MST Thursday. The heaviest snow will occur
  this afternoon and evening. 

* IMPACTS...Dangerous travel conditions due to icy, snow covered
  roads and reduced visibilities in heavy snow. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

CLH
1 follow-up statement
235 
WWUS45 KCYS 181001
WSWCYS

URGENT - WINTER WEATHER MESSAGE
National Weather Service Cheyenne WY
301 AM MST Thu Feb 18 2021

...SNOW AND BLOWING SNOW WILL LEAD TO HAZARDOUS ROAD CONDITIONS
ALONG THE I-80 CORRIDOR BETWEEN LARAMIE AND RAWLINS THIS AFTERNOON
THROUGH FRIDAY AFTERNOON...


WYZ116-181115-
/O.CAN.KCYS.WS.W.0007.000000T0000Z-210218T1200Z/
South Laramie Range-
Including the cities of Buford, Pumpkin Vine, and Vedauwoo
301 AM MST Thu Feb 18 2021

...WINTER STORM WARNING IS CANCELLED...

Light snowfall is largely over with areas of dense fog remaining
in its place; therefore, have opted to cancel the Advisory. Roads
remain slick and fog has reduced visibilities to drive carefully
if traveling this morning.

$$

WYZ117-181115-
/O.CAN.KCYS.WW.Y.0016.000000T0000Z-210218T1200Z/
South Laramie Range Foothills-
Including the cities of Whitaker, Federal, and Horse Creek
301 AM MST Thu Feb 18 2021

...WINTER WEATHER ADVISORY IS CANCELLED...

Light snowfall is largely over with areas of dense fog remaining
in its place; therefore, have opted to cancel the Advisory. Roads
remain slick and fog has reduced visibilities to drive carefully
if traveling this morning.

$$

WYZ110-200000-
/O.NEW.KCYS.WW.Y.0017.210218T2300Z-210220T0000Z/
North Snowy Range Foothills-
Including the cities of Arlington and Elk Mountain
301 AM MST Thu Feb 18 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 PM THIS AFTERNOON TO
5 PM MST FRIDAY...

* WHAT...Snow and blowing snow expected. Total snow accumulations
  of up to one inch. Winds gusting as high as 70 mph. A High Wind
  Warning is in place as well.

* WHERE...Arlington to Elk Mountain along Interstate 80 between 
  Laramie and Rawlins.

* WHEN...From 4 PM this afternoon to 5 PM MST Friday.

* IMPACTS...Plan on slick road conditions due to blowing and
  drifting snow. Falling and blowing snow could significantly 
  reduce visibility below one half mile at times. The hazardous 
  conditions could impact the morning or evening commute. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 17, 12:06 PM MSTWinter Weather AdvisoryCYSAlbany, Laramie15 hr
Feb 17, 2:32 PM MSTHigh Wind WatchCYSAlbany, Carbon, Laramie, Platte13 hr

Nearby

Winter Storm Warnings in Wyoming, 2021Every winter storm 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.