A progressive Pacific trough trekked across eastern Utah. Mild southwest flow ahead of the storm kept temperatures well above normal before the trough moved through during the overnight hours.
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The episode as NWS GJT wrote it up.
A progressive Pacific trough trekked across eastern Utah. Mild southwest flow ahead of the storm kept temperatures well above normal before the trough moved through during the overnight hours. Rain fell in the valleys before changing over the snow. Moderate snowfall totals were reported over the La Sal and Abajo Mountains.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Jan 29, 4:44 PM MST, 1 hour 16 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 444 PM MST Fri Jan 29 2021 .SHORT TERM...(Tonight through Saturday night) Issued at 200 PM MST Fri Jan 29 2021 Temperatures have warmed dramatically this afternoon thanks to strong southwesterly flow over eastern Utah and western Colorado. Several mountain wave cloud features can be noted on satellite imagery today, and favored valleys in downslope flow have quickly soar into the 50s today thanks to enhanced compressional warming. As the afternoon progresses, expect an increase in cloud cover as our next storm system approaches from the west. The timing of this system has slowed somewhat, and mountain snow shower activity is unlikely anywhere before 6pm. The southeast Utah ranges and San Juans will see snow first this evening by 8pm or so, with light snow overspreading the remainder of the higher terrain of eastern Utah and western Colorado before midnight. Valley locations should see their best opportunity for precipitation along and just behind the passage of a cold front, set to move through in the 9pm to midnight timeframe. Short-term forecast soundings support around 1-3 hours of precipitation for places such as Grand Junction, Delta, and Montrose. Showers will change to snow quickly, with around a coating to possibly a half inch expected in the aforementioned towns. Farther south along the US 160 corridor, frontal precipitation will be assisted by upslope southerly flow, and a 2-4 inch event is likely from Cortez through Pagosa Springs. The southern San Juan mountains still look to do the best from this system, where a model average of 5 to 10 inches of snow appears likely...with up to a foot in some of the favored southerly aspects. The only lingering uncertainty remains the Grand Mesa and central mountains of Colorado. While these locations will likely see a burst of moderate snow this evening as the front passes...the key will be how much moisture exists in the post- frontal northwesterly flow regime later tonight into early Saturday morning. We will stick to a general 4-6 inch forecast for these locations for now, however it would not be completely surprising to squeeze out a few more inches than that if favorable dendritic growth can occur behind the front. Accumulating snow will come to an end on Saturday morning before noon, with orographic snow showers ending in the early afternoon hours. Expect a much colder day on Saturday, with stiff northwesterly flow present area-wide. Skies are expected to quickly clear on Saturday evening setting the stage for a clear, dry, and cold night with favorable radiational cooling conditions present after evening winds diminish. .LONG TERM...(Sunday through Friday) Issued at 200 PM MST Fri Jan 29 2021 The coming week will start under the influence of a ridge of high pressure. Quiet conditions and high temperatures a few degrees warmer than average are expected for Monday and Tuesday. Clouds will begin to increase Tuesday afternoon as the next Pacific Northwest system begins to exert its influence. Confidence regarding the details of this upcoming system is increasing, but slowly. Taking a look at the available ensemble guidance, it seems the biggest uncertainty is in timing and position of the trough. The GEFS prefers a shallower, more progressive trough while the ECMWF ensemble is favoring a slower, deeper trough. The ensembles and the deterministic models do agree on the general progression and track of the system, with the base of the trough moving over the Four Corners area Wednesday afternoon/evening. This is a favorable track for widespread precipitation in western Colorado and eastern Utah as it moves the best upper dynamics and lift over the region. Lift isn't everything though, moisture is still needed to have precipitation. Models are in good agreement that the moisture will be there though. Ensemble PWATs are forecasted to be 150-200% of normal for the entire CWA, even up to 250% of normal south of the San Juan mountains. It appears that this system will be tapping into some deep tropical Pacific moisture and dragging it up into Colorado and New Mexico. All together, this mid-week system is looking more promising as models continue to come into agreement. That doesn't mean there won't be major shifts to the forecast, as there are still 4-5 days between now and when the system begins affecting the CWA. However, at this point, precipitation is forecast to begin late Tuesday to early Wednesday, and should come to an end some time late Thursday. Temperatures for this period will also be cooler than normal. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 444 PM MST Fri Jan 29 2021 Mid to high level clouds passing overhead attm with patterns suggesting mountain wave turbulence is likely. The next storm system is on the western doorstep and expect lowering cigs and visibility by mid evening with many forecast terminals under VFR by 06z with some just before this time and other lingering beyond into the mid morning hours on Saturday. General improvement is expected through the afternoon tho ILS cigs may persist over the KEGE and KASE terminals into the evening hours. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...Winter Weather Advisory until 8 AM MST Saturday for COZ019. UT...None. && SHORT TERM...MAC LONG TERM...BGB AVIATION...TGJT
Hazardous Weather Outlook National Weather Service Grand Junction CO 450 AM MST Fri Jan 29 2021 COZ001>014-017>023-UTZ022>025-027>029-301400- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops- Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide- Northwest San Juan Mountains-Southwest San Juan Mountains- Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 450 AM MST Fri Jan 29 2021 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Clouds will increase over the region today with some light snow possible over the southwest San Juans this afternoon. Showers will increase this evening and continuing overnight with a combination of rain and snow in the valleys with snow in the mountains. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Snow showers will persist on Saturday before high pressure rebuilds on Sunday and remains in place until early next week. Several inches of snow are possible in the mountains by Saturday afternoon. The next storm system looks to arrive mid-next week, bringing the potential for widespread precipitation back to the region. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
Generally 7 to 13 inches of snow fell across the La Sal Mountains with 4 to 6 inches in the Abajos.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2021Every state in 2021This day in weather historyWarnings in Utah, 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: 930936.