A Pacific low pressure system moved across northern Colorado and produced moderate snowfall over the Snowy Range and adjacent foothills. Gusty northeast winds to 30 mph created areas of blowing snow in open areas.
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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.
A Pacific low pressure system moved across northern Colorado and produced moderate snowfall over the Snowy Range and adjacent foothills. Gusty northeast winds to 30 mph created areas of blowing snow in open areas.
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 Apr 3, 3:14 PM MST, 10 hours 46 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 414 PM MDT Mon Apr 3 2017 .SHORT TERM...(This evening through Wednesday) Issued at 345 PM MDT Mon Apr 3 2017 Afternoon water vapor imagery showed the main shortwave trough tracking southeast into the southern Great Basin. Wraparound moisture from departing shortwave over SD and weakness/marginal instability aloft aiding in scattered shower development across much of the CWA. Most of the convection will gradually wind down this evening, but increase again tonight and Tuesday as the Great Basin trough tracks east and forms a closed low over northern New Mexico Tuesday morning. Models continue to trend a bit further south with each run. Rain/snow shower coverage will be highest over the mountains, with more scattered coverage for lower elevations. Regarding snowfall accumulations, snow levels lower to 5000 feet tonight and 5500 feet Tuesday. In agreement w/ WPC 18Z guidance of heavier snow over CO Front Range. Generally expect 2-5 inches over Snowy/Sierra Madre ranges, with an inch or less for lower elevations. Pressure gradient tightens Tuesday, with brisk north-northeast winds. It will be much cooler with low level cold air advection in place. Expect highs 10-15 degrees below normal with 30s and 40s. The precipitation will taper off from north to south Tuesday evening with subsidence pattern aloft. Wednesday will be milder with high temperatures closer to normal. 700mb winds increase to near 40 kt from west-northwest Wednesday, so it wil be breezy to windy, mainly along the I-80 corridor. .LONG TERM...(Tuesday night through Monday) Issued at 200 PM MDT Mon Apr 3 2017 Wednesday night/Thursday...Rather high amplitude ridge aloft moves overhead with return southerly winds at the surface. With limited low and mid level moisture and no lift, no precipitation expected. Moderating airmass produces a more mild overnight Wednesday night and a relatively mild Thursday. Friday...Ridging aloft moves off to our east with zonal flow developing over our forecast area. Continued dry with limited low and mid level moisture. Warming trend continues based on thicknesses and 700 mb temperature changes. Saturday...Flow aloft turns southwest and strengthens, producing a windy day regionwide. Afternoon showers possible over our far western counties west of a Douglas to Laramie line, in advance of the approaching shortwave aloft. Sunday...Rather potent shortwave trough aloft and associated cold front move west to east across our forecast area, producing isolated to scattered showers, least numerous over our southeast counties due to downsloping. Monday...Low amplitude ridging aloft develops, though enough diffluence aloft ahead of the approaching shortwave aloft to produce isolated to scattered showers. Cooler with more cloud cover and upslope winds, along with thickness and 700 mb temperatures falls. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 410 PM MDT Mon Apr 3 2017 Wyoming TAFS...VFR at Cheyenne until 04Z, then MVFR until 06Z, then IFR until 15Z, then MVFR until 19Z, then VFR. VFR at Laramie until 06Z, then MVFR until 18Z, then VFR. VFR at Rawlins until 08Z, then MVFR until 16Z, then VFR. Nebraska TAFS...MVFR at Scottsbluff until 10Z, then IFR until 15Z, then VFR. MVFR at Chadron until 18Z, then VFR. MVFR at Sidney until 06Z, then IFR until 15Z, then VFR. MVFR at Alliance until 09Z, then IFR until 15Z, then MVFR until 19Z, then VFR. && .FIRE WEATHER... Issued at 208 PM MDT Mon Apr 3 2017 Occasional rain and snow showers will continue tonight and Tuesday with the passage of a upper level low pressure trough. Measurable snowfall will be confined to elevations above 5000 feet. Minimum humidities of 45 to 50 percent Tuesday will lower to 25 to 30 percent Wednesday and Thursday. Breezy to windy conditions are expected Wednesday and Friday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...MAJ LONG TERM...RUBIN AVIATION...RUBIN FIRE WEATHER...MAJ
Hazardous Weather Outlook National Weather Service Cheyenne WY 459 AM MDT Mon Apr 3 2017 WYZ101>119-041100- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen 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-East Laramie County- 459 AM MDT Mon Apr 3 2017 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Another upper level low pressure system will move across the central Rockies later today and tonight. Light to moderate snow will develop in the high country out west, with light snow possible across Converse and Niobrara Counties as well. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY Periods of snow will continue through Tuesday morning. Storm total accumulations of 3 to 6 inches are possible for elevations above 9000 ft, with locally higher amounts along northeast facing slopes. An inch or less of snowfall is expected elsewhere in the high country, with just a dusting across the plains of southeast Wyoming. Windy conditions look to return to the wind prone areas along and west of Interstate 25 on Wednesday morning, and again for Friday and Saturday. Gusts around 50 mph are possible. .Spotter information statement... Spotter activation will not be needed. NEZ002-003-019>021-054-055-095-096-041100- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 459 AM MDT Mon Apr 3 2017 This hazardous weather outlook is for portions of western Nebraska. .DAY ONE...TODAY AND TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY The probability for widespread hazardous weather is low. .Spotter information statement... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
3 winter weather. Local standard time, as filed.
The Sand Lake SNOTEL site (elevation 10050 ft) estimated six inches of snow.
The Medicine Bow SNOTEL site (elevation 10500 ft) estimated six inches of snow.
Two to four inches of snow was observed along Interstate 80 from Arlington to Elk Mountain.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2017Every state in 2017This day in weather historyWarnings in Wyoming, April 2017
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: 692560, 692561, 692562.