A weak cold front brought light snow showers to northern Reno and areas of the northeastern Lake Tahoe Basin. Very minor travel impacts were seen.
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The episode as NWS REV wrote it up.
A weak cold front brought light snow showers to northern Reno and areas of the northeastern Lake Tahoe Basin. Very minor travel impacts were seen.
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 Reno, NV wrote its last area forecast discussion before the first event at Dec 11, 3:20 AM PST, 4 hours 40 minutes earlier.
Area Forecast Discussion National Weather Service Reno NV 320 AM PST Fri Dec 11 2020 .SYNOPSIS... Rain and snow arrive tonight into Saturday morning as a cold front drops into the region from the north. Snowfall in the Sierra and for portions of far northeast California and northern Nevada could bring travel concerns. Another system arrives on Sunday for more travel concerns for portions of the Sierra and northeast California. Quieter weather briefly returns early next week before additional systems possibly affect the region. && .SHORT TERM... Taking a look at current conditions, it remains very dry across far southern Douglas and Lyon counties as well as for Mono County this morning with humidities 5-15%. Fortunately, winds have come down from earlier with gusts mainly up to 25 mph. Wind gusts may come up again late this afternoon and tonight; however, humidities should be trending up late today and tonight for a lessening of the fire spread threat. A somewhat complicated pattern is in the offing through Sunday with some smaller-scale details key for possible impacts from periods of light snow, with the largest uncertainty across northwest Nevada as well as west-central Nevada north of Hwy 50. Periodic gusty winds are also of some concern. The feature of interest for bringing snow and lower valley rain and snow is currently off the British Columbia coast. That area of low pressure will drop into the Pacific Northwest today before moving into the northern Rockies and eastern Great Basin tonight. As the low drops south, it will push a cold front into northeast CA and the northern half of Nevada. As the upper forcing with the low works into the region, a band of precipitation is expected to develop over far northeast CA and northern NV, with the band sagging south into central NV and portions of west-central NV. Precipitation type is looking to be mainly snow above 4000-4500 feet with areas north of Lovelock and Susanville, and along Hwy 50 well east of Fallon, likely to at least see a period of light snow tonight into Saturday morning. For far western NV and south of Hwy 50, precipitation looks to remain light with little or no snow accumulation as snow levels are expected to rise above valley floors ahead of the cold front. For the Sierra, ahead of the frontal precipitation there could be a period of light warm air advection snow which is likely to bring travel concerns over passes. For the Lake Tahoe Basin, snowfall is more uncertain as snow levels will be rising into Saturday although as mentioned the passes above 7000 feet are still likely to be snow per the latest simulations. Overall, snowfall amounts through Saturday look fairly modest from a relative sense; however, it doesn't take much to cause travel headaches, especially on more heavily traveled routes like I-80 and Hwy 395. For the Sierra, perhaps 4-8" above 6500-7000 feet (locally higher near crest) is on tap with perhaps a couple inches down to 5500-6000 feet. For far northeast CA and out into west- central NV, around 1-3" is possible Friday night and Saturday above 4000-4500 feet. Later Saturday into early Sunday will be a break before the next wave moves across northern CA and northern NV from the west. That will generally be a more typical system off the Pacific although it looks quite progressive so snowfall amounts again looks fairly modest by Sierra standards. Still, with some 6-12" in the high Sierra (highest north of Mono County) by late Sunday evening and up to 3" into northeast CA above ~5000 feet, possibly more in the Tahoe Basin, travel impacts are again likely. For western NV, any precipitation could end as light snow showers late Sunday night so some areas of slick conditions will be possible, especially above 5000 feet. Wind-wise, gusty winds of 25-35 mph or so are still expected throughout much of the region on Sunday. A bit higher winds with some downslope component remain possible in the Sierra Front in western Nevada down to northern Mono County; however, the airmass is expected to be much moister than the current one with some spillover, especially north of Hwy 50, so significant downslope wind chances look low at this time. -Snyder .LONG TERM...Monday into next weekend... Not a significant change to the long term forecast this morning. Confidence is moderate through Tuesday then low for Wednesday and beyond. All models show a break Monday into Tuesday, but then differ on the storm potential for the latter half of the week into next weekend. Monday will be cooler in the wake of the weekend storm with lighter winds and temperatures near seasonable for mid-December. A bit of warming for Tuesday under a short wave ridge before model agreement really breaks down. Overall the ensembles are not that bullish on any decent storms for the latter half of the week. However, there are quite a few members that are somewhat wet from at least I-80 north. On either side of the mean though, you have the operational EC which is dry with a moderate amplitude ridge. The GFS is an extreme outlier with a potent storm. Cluster tools show the EC more likely than the GFS, but we will continue with the mean for now given the wide variation. This will keep temps a little above average with a slight chance of rain/snow from I-80 north Wednesday onward. While that is the official forecast for now, expect changes the next couple days or so. X && .AVIATION... Main concern will be the storm that will move through starting tonight and into Saturday morning. Winds at ridge level will be near 50 kts with some LLWS for the Tahoe and Sierra Front terminals from 03-15Z Sat. Winds at the surface do not look too strong, but KTRK and KTVL will gust to 30 kts at times during this time. After 15-18Z the front will move through with a more consistent NW wind gusting around 25 kts for all terminals. There will be some snow also, most likely in the Sierra from KTVL northward and into NE California around KSVE to the Oregon Border. Expect IFR conditions peaking from 03-12Z which will coincide with the LLWS above. Any runway accumulation looks to be 2 inches or less. After 15Z, expect a few -SHSN to continue, but mostly in the Sierra and into central NV. A brief break Saturday night before the next storm moves in. At this point, after 18Z Sunday into Monday morning will be the best chance for RA/SN along with LLWS. We expect MVFR conditions into western NV at times with IFR in the Sierra during this time. X && .REV Watches/Warnings/Advisories... NV...None. CA...None. && For more information from the National Weather Service visit... http://weather.gov/reno
Special Weather Statement National Weather Service RENO NV 439 AM PST Fri Dec 11 2020 CAZ070>073-NVZ001>005-121200- Surprise Valley California-Lassen-Eastern Plumas- Eastern Sierra Counties-Greater Lake Tahoe Area-Mono County- Mineral and Southern Lyon Counties-Greater Reno-Carson City- Minden Area-Western Nevada Basin and Range including Pyramid Lake- Northern Washoe County- Including the cities of Cedarville, Eagleville, Fort Bidwell, Portola, Susanville, Westwood, Sierraville, Loyalton, South Lake Tahoe, Tahoe City, Truckee, Markleeville, Bridgeport, Coleville, Lee Vining, Mammoth Lakes, Hawthorne, Yerington, Smith Valley, Mina, Schurz, Stateline, Glenbrook, Incline Village, Sparks, Verdi, Gardnerville, Virginia City, Fernley, Fallon, Lovelock, Silver Springs, Nixon, Imlay, Empire, and Gerlach 439 AM PST Fri Dec 11 2020 ...WINTER WEATHER ADVISORIES FOR LAKE TAHOE AND PORTION OF NORTHEAST CALIFORNIA AND NORTHERN NEVADA... Snowfall potential has increased for the Lake Tahoe area, especially above 6500 feet, as well as for areas north of Susanville and Lovelock for tonight into Saturday. See the winter statements for more information in those areas. Elsewhere across western Nevada and south of Lovelock in west-central Nevada, only minimal snowfall amounts are expected at best through Saturday. Another system is expected for Sunday and Sunday night with additional snowfall impacts to travel expected in the Sierra and for northeast California. A light snowfall is possible elsewhere into western and west-central Nevada, especially in foothills above 5000 feet; however, impacts there are quite uncertain at this time. http://weather.gov/reno
The national radar mosaic for the moment the first event began.
2 winter weather. Local standard time, as filed.
Up to an inch of snow fell above 7000 feet in the northern portion of the Carson Range bordering the Lake Tahoe Basin.
Very light snowfall less than an inch fell across portions of north Reno.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nevada in 2020Every state in 2020This day in weather historyWarnings in Nevada, December 2020
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: 938969, 938970.