A Pacific storm system brought heavy snow to the eastern slopes of the Sierra Nevada.
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The episode as NWS VEF wrote it up.
A Pacific storm system brought heavy snow to the eastern slopes of the Sierra Nevada.
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 Las Vegas, NV wrote its last area forecast discussion before the first event at Dec 22, 1:45 PM PST, 5 hours 15 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 145 PM PST Wed Dec 22 2021 .SYNOPSIS...Light snow over the southern Sierra Nevada will increase tonight into Thursday with rain and higher elevation snow spreading across the Mojave Desert and Southern Great Basin Thursday through Friday. Weather pattern remains active through the weekend into next week with additional shower chances, cooler temperatures and lowering snow levels. && .DISCUSSION...Through Friday night. Satellite shows weak atmospheric river moving through central California this afternoon. Radar/surface observations indicate there is light rain along the central coast spreading up the windward side of the southern Sierra. Precipitation intensity will increase with a better shot of precipitation spilling over the Sierra Thursday as wind aloft increase due to a trough sagging further south down the west coast. AR tools shows higher IVT values directed into the southern Sierra as well which supports the onset of heavier precipitation. Still only expecting light precipitation amounts to develop across the Owens Valley and higher terrain of the southern Great Basin tomorrow as the Sierra intercept most of the moisture. Trough will continue to sag south through Thursday night before turning inland across southern California into Arizona Friday. This is when we expect most of the precipitation to spread across the Mojave Desert and western Arizona. AR tools continue to indicate a robust AR directed into southern California into western Arizona. For southern Nevada, the AR is at its peak Thursday night with values tapering off Friday. Still looking at a least a 0.25" for most valley floors in the Mojave Desert with higher amounts (0.50-1.00") for Mohave County and the Morongo Basin. Snow levels expected to stay above Mountain Pass on I-15 and higher elevations of eastern Mohave County (I-40) for the entire event so not looking at any snow issues for travelers. Spring Mountains remain a bit complicated. Expecting rain through most of Thursday night before snow levels lower to about 7500 feet by 4 am Friday morning. Snow levels will gradually lower to about 7000 feet by late Friday morning. After that precipitation amounts will taper off as snow levels do lower to about 6500 late Friday afternoon. Not confident at this point to issue a Winter Weather Advisory as afraid much of the precipitation will fall as rain with only a slushy mess accumulating behind the main slug of QPF. For this forecast, do show 2-5 inch accumulations in Kyle Canyon and 3-7 inches in Lee Canyon over a 48-hour period between 4 am Thursday and 4 am Saturday. Breezy to windy at higher elevation during the period with temperatures near to slightly above normal. Saturday - Wednesday...Not much has changed for this period. Longwave trough across the west will keep the region cool, breezy with rounds of showers possible as individual disturbances move through the trough. && .AVIATION...For Harry Reid...Light winds following typical diurnal trends are forecast into Thursday morning. However, by 18Z Thursday the approaching west coast trough will cause winds to come around to the southwest and increase to greater than 10kts. Mid-to-high level clouds will continue to thicken today and tonight. Cloud bases are forecast to remain AOA 10kft into Thursday morning before lowering to 060-090kft by Thursday afternoon. While precipitation will begin falling on the Spring mountains and Sheep Range Thursday morning, no precipitation is forecast at the terminal until later in the afternoon on Thursday. For the rest of southern Nevada, northwest Arizona and southeast California...With the exception of KBIH, winds will continue to be light and follow typical diurnal variations through Thursday morning. Clouds cover will continue to increase to BKN-OVC at all sites with bases generally being AOA 10kft. For KBIH, light variable winds along high overcast will continue into this evening. Lower cloud bases along the ridges should not make it into the valley until late this evening when CIGs will fall to 030-050kft. VCSH is likely west of the terminal starting after 10Z with a better chance of -SHRA after 12Z. Precipitation is expected to remain liquid through the TAF period. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && DISCUSSION...Pierce AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Eighteen inches of snow fell in Aspendell.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, December 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: 996343.