A cold pool aloft and a moist upslope flow produced a brief period of moderate to heavy snow over the southern Laramie Range. Four inches of snow was observed at the Interstate 80 summit.
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The episode as NWS CYS wrote it up.
A cold pool aloft and a moist upslope flow produced a brief period of moderate to heavy snow over the southern Laramie Range. Four inches of snow was observed at the Interstate 80 summit.
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 Sep 23, 10:33 PM MST, 1 hour 27 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 1133 PM MDT FRI SEP 23 2016 UPDATE Issued at 1128 PM MDT Fri Sep 23 2016 We are sending out a quick update to issue a winter weather advisory for Vedauwoo, Buford and the Summit area. Latest look at the radar was indicating more snowfall moving towards this area with slick roads already developing, according to the webcams. Winter weather advisory will be in effect until 3 am. UPDATE Issued at 1022 PM MDT Fri Sep 23 2016 I-80 webcams indicated light-moderate snow falling over the south Laramie Range and foothills where temperatures were in the lower 30s. Accumulations will be less than an inch for the grassy areas, with little or no accumulation on the roadways. Snow showers will continue for the next several hours. UPDATE Issued at 848 PM MDT Fri Sep 23 2016 Cancelled Severe Thunderstorm Watch early this evening as better shear and instability moved northeast into western SD. There were several reports of large hail and damaging winds across portions of eastern WY and the northern NE panhandle during the late afternoon. A strong cold front pushed east of the CWA this evening, with some thunderstorms lingering over the NE panhandle until midnight. Otherwise, occasional showers will continue tonight. Temperatures will be cold enough for snow above 9000 feet, however little or no accumulation is expected. West to northwest winds will remain rather gusty tonight due to the tight post-frontal pressure gradient. && .SHORT TERM...(This evening through Sunday night) Issued at 215 PM MDT Fri Sep 23 2016 Active weather pattern across the CWA early this period with showers and thunderstorms...some strong or even severe...along with some mtn snows. All this in association with a strong upper low currently beginning to lift northeast around the Utah/Wyoming border. band of showers and a few storms now progressing into central Wyoming and this will continue to move slowly east through this evening with individual showers and storms in this band moving quickly north. Some potential for a few strong to severe storms the rest of this afternoon given modest CAPE values and good shear. Strong winds the main threat given the fast speeds of any storms with some marginally severe hail possible as well. Activity will move into the high plains tonight as the upper low moves northeast across Wyoming. On Saturday the upper low will move over the northern plains with downsloping flow expected to dry things out east of the mtns. Wrap-around moisture will bring some rain and snow showers to western parts of the CWA with a few inches of snow over the higher mtns mainly saturday morning. All pcpn should end Saturday evening as the upper low moves over North Dakota and the main trof axis moves by the area. Cool saturday night with dry and mild weather on Sunday. There also could be a relatively short period of stronger winds in the wind-prone areas of southeast Wyoming Saturday morning. Will hold off on a watch as speeds look marginal relatively localized only for a short time. Still...some gusts around 50 mph possible. .LONG TERM...(Monday through Friday) Issued at 215 PM MDT Fri Sep 23 2016 A transition to warmer and drier weather is expected through most of the extended forecast period as upper-level ridging builds back into the area. The GFS and ECMWF both suggest a weak trough under-cutting the ridge and lifting across the central Rockies on Wednesday and/or Thursday, possibly resulting in isolated showers and thunderstorms. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1013 PM MDT Fri Sep 23 2016 Showers will continue overnight, producing occasional MVFR cig/vis. The mountains will be obscured by low cigs and snow showers. Gusty northwest to west winds 25-35 kt will continue as well. Brief -TSRA will impact the western Nebraska terminals until 08Z. Cig/vis improve to VFR east of the Laramie Range by morning, with MVFR cig persisting at RWL thru the day. Scattered showers will be possible west of the Laramie Range Saturday with VCSH at RWL and LAR. West winds will gust 25-30 kt Saturday. && .FIRE WEATHER... Issued at 215 PM MDT Fri Sep 23 2016 Overall fire weather concerns expected to remain low through the weekend into early next week. A cold front will move across the district through this evening with a band of showers and thunderstorms accompanying it. Breezy and cooler Saturday with mild and mainly dry weather expected Sunday into early next week. && .CYS Watches/Warnings/Advisories... WY...None. NE...None. && UPDATE...REC SHORT TERM...RE LONG TERM...CLH AVIATION...MAJ FIRE WEATHER...RE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1150 PM MDT FRI SEP 23 2016 WYZ101-103>107-109>118-250200- CONVERSE COUNTY LOWER ELEVATIONS-NORTH LARAMIE RANGE- FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-CENTRAL CARBON COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY- SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE- LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS- CENTRAL LARAMIE COUNTY- 1150 PM MDT FRI SEP 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TONIGHT OCCASIONAL RAIN SHOWERS WITH HIGH ELEVATION SNOW SHOWERS WILL CONTINUE TONIGHT. LITTLE OR NO ACCUMULATION IS EXPECTED BELOW 7000 FEET. HOWEVER, ROADWAYS WILL BECOME SLICK OVER THE I-80 SUMMIT AND VEDAUWOO. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. NEZ002-003-019>021-054-055-095-096-WYZ102-108-119-250200- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX-NIOBRARA COUNTY-GOSHEN COUNTY- EAST LARAMIE COUNTY- 1150 PM MDT FRI SEP 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN NEBRASKA...EAST CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TONIGHT ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE UNTIL MIDNIGHT. BRIEF GUSTY WINDS TO 40 MPH AND HEAVY RAIN WILL ACCOMPANY THE STRONGER STORMS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 1021 PM MDT FRI SEP 23 2016 WYZ116-240630- SOUTH LARAMIE RANGE- INCLUDING THE CITIES OF...BUFORD...PUMPKIN VINE...VEDAUWOO 1021 PM MDT FRI SEP 23 2016 MODERATE SNOW IS OCCURRING NEAR VEDAUWOO AND THE SUMMIT ALONG I-80. THE SNOW IS NOT EXPECTED TO ACCUMULATE MUCH ON THE ROADWAYS, BUT THOSE TRAVELING SHOULD BE AWARE OF ANY SLICK SPOTS THAT MAY DEVELOP. THE SNOW MAY LINGER DURING THE NEXT COUPLE OF HOURS.
The national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
Four inches of snow was reported at the Interstate 80 summit.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2016Every state in 2016This day in weather historyWarnings in Wyoming, September 2016
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: 654179.