Heavy snow was measured across much of Carbon County starting late on the 22nd through the early morning of the 24th. SNOTEL sensors in the Sierra Madre and Snowy Range measured over a foot of snow while out by Rawlins and Muddy Gap observers noted over six inches of snowfall.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
Heavy snow was measured across much of Carbon County starting late on the 22nd through the early morning of the 24th. SNOTEL sensors in the Sierra Madre and Snowy Range measured over a foot of snow while out by Rawlins and Muddy Gap observers noted over six inches of snowfall.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Cheyenne, WY wrote its last area forecast discussion before the first event at Jan 22, 2:42 PM MST, 2 hours 18 minutes earlier.
Area Forecast Discussion
National Weather Service Cheyenne WY
242 PM MST Fri Jan 22 2021
.SHORT TERM...(This evening through Sunday)
Issued at 245 PM MST Fri Jan 22 2021
Key Messages:
1) Winter Storm Warnings are out for the Sierra Madre and Snowy
Ranges starting at 5 PM MST due to snowfall amounts between 10 and
14 inches, with upward of 20 inches possible for isolated areas
of higher elevation. Winter Storm Warnings are also out for the
Shirley Mountains, Muddy Gap, and the Rawlins area due to extended
periods of moderate to heavy snowfall dropping 5 to 8 inches by
Sunday morning. Major travel impacts anticipated, especially along
Interstate-80 between Laramie and Rawlins.
2) Winter Weather Advisories are out for areas surrounding the
Winter Storm Warnings because of snowfall amounts between 3 and 6
inches anticipated between Friday night and Sunday morning.
------
Scattered light snow showers will occur Saturday into early Sunday
across Laramie, Platte, and Goshen Counties, as well as the
Nebraska Panhandle. Accumulations of 1-2 inches are anticipated
with limited travel impacts. Portions of the Laramie Valley may
require a Winter Weather Advisory depending on how heavy the
snowfall is and how long the snow sticks around, but as of right
now, we are only forecasting 1 to 2 inches of snowfall between
Friday night and Sunday morning for the Laramie Valley.
Temperatures will be in the 20s and 30s during the day across SE
WY and the NE Panhandle, with temperatures in the teens in the
mountains. At night, the low temperatures will drop to the lower
teens. Some positive highlights for SE WY and the NE Panhandle are
that this system is bringing some much needed moisture to the
region that should keep humidities between 50 and 100 percent for
the next few days! Also, the winds should stay between 5 and 10
MPH between now and Sunday. So we are getting some much needed
snowfall and a break from the winds!
.LONG TERM...(Sunday night through Friday)
Issued at 245 PM MST Fri Jan 22 2021
Snow coming to an end Sunday night as system moves east into the
central plains. Mainly dry Monday as we are in between systems.
Begin to see an increase in precip chances Tuesday as another low
pressure system tracks across Colorado. Highest PoPs across the
I-80 Corridor from Sidney to Arlington that runs Tuesday afternoon
through early Wednesday morning.
Strong winds possible Wednesday night into Thursday as GFS 700mb
winds increase to 50-55kts across southeast Wyoming. Looks like we
remain on the subsident side of a 110kt jest that lays across
central Wyoming. Still a ways out...but a good pattern for strong
winds.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1030 AM MST Fri Jan 22 2021
Tricky and difficult forecast for the 18Z TAFs. Guidance not
picking up on current band of snow moving through KRWL. So using
persistence and radar/satellite trends on moving the snow out of
KRWL this afternoon. Main snow event still looks on track for
this evening into Saturday with widespread IFR conditions after
06Z or so tonight.
&&
.FIRE WEATHER...
Issued at 342 AM MST Fri Jan 22 2021
Limited to no fire concerns with humidity values well above critical
values and scattered snow showers today and more snow through the
weekend, especially for the higher terrain west of I-25. More limited
snow amounts expected for the High Plains but higher humidity and lower
winds will keep fire weather conditions in check over the weekend.
Long term drought conditions remain in place with limited soil
absorption from the snow and frozen ground.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Warning from 5 PM this afternoon to 5 AM MST Sunday
for WYZ112-114.
Winter Weather Advisory from 5 PM this afternoon to 5 AM MST
Sunday for WYZ110-111-113.
Winter Storm Warning from 11 PM this evening to 5 AM MST Sunday
for WYZ104-109.
Winter Weather Advisory from 11 PM this evening to 5 AM MST
Sunday for WYZ101>103-105.
NE...None.
&&
SHORT TERM...LK
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...JSAHazardous Weather Outlook National Weather Service Cheyenne WY 133 PM MST Fri Jan 22 2021 WYZ101>105-109>114-232045- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Carbon County-North Snowy Range Foothills- Southwest Carbon County-Sierra Madre Range- Upper North Platte River Basin-Snowy Range- 133 PM MST Fri Jan 22 2021 This hazardous weather outlook is for southcentral Wyoming...east central Wyoming...and southeast Wyoming. .DAY ONE...THIS AFTERNOON AND TONIGHT Winter Weather Advisories and Winter Storm Warnings go into effect starting at 5 PM due to widespread snowfall. 10-14 inches of snow from 8000-9000 feet is likely with upwards of 20 inches possible above 9000 feet by Sunday. Major travel impacts, especially along Interstate 80 between Laramie and Rawlins, as well as Interstate 25 from Douglas to Casper. Slick roads and limited visibilities at times. Caution is advised for anyone located and recreating in this area. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY Moderate to at times heavy snowfall continues throughout Saturday and into Sunday morning. Travel will be difficult, especially along Interstate 80 between Laramie and Rawlins. Please avoid getting lost if snowmobiling in the high terrain. After Sunday, probability for hazardous weather is low. .Spotter information statement... Spotters in these areas are encouraged to share snowfall reports with the National Weather Service. NEZ002-003-019>021-054-055-095-096-WYZ106>108-115>119-232045- Dawes-Box Butte-Scotts Bluff County-Banner County-Morrill- Kimball County-Cheyenne-North Sioux-South Sioux- Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Laramie Valley- South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 133 PM MST Fri Jan 22 2021 This hazardous weather outlook is for the Nebraska panhandle...and southeast Wyoming including Laramie, Platte, and Goshen Counties. .DAY ONE...THIS AFTERNOON AND TONIGHT Light snow showers will occur tonight into Saturday, but impacts will be limited. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY Scattered light snow showers will occur Saturday into early Sunday, but accumulations should be 1 to 2 inches. Overall impacts will be low. After Sunday, probability for hazardous weather is low. .Spotter information statement... Spotters in these areas are encouraged to share snowfall reports with the National Weather Service. LK
The national radar mosaic for the moment the first event began.
4 heavy snow. Local standard time, as filed.
Medicine Bow sensor at elevation of 10,500 feet measured a snow water equivalent of 1.0 inches and applying a snow to liquid ratio of fifteen to one gave estimated snowfall of 15.0 inches.
Old Battle sensor at elevation of 10,000 feet measured a snow water equivalent of 1.2 inches and applying a snow to liquid ratio of fifteen to one gave estimated snowfall total of 18.0 inches.
Heavy snow averaging six inches according to plow drivers between Muddy Gap and Rawlins on Highway 287 and 789.
Observer located four miles west of Rawlins measured 8.0 inches of snowfall.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2021Every state in 2021This day in weather historyWarnings in Wyoming, January 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 931955, 931956, 931953, 931954.