After a couple days of sunshine and clearing, winter weather will return to the Sierra and Carson City region this week, extending through Christmas and beyond, according to the National Weather Service in Reno.
A series of Pacific winter storms will bring periods of stormy weather to much of California and Nevada next week. There will be few, if any, meaningful breaks in the weather for the Sierra once the storms begin on Tuesday, so plan ahead, NWS forecasters advise.
Through Monday: Quiet weather, light winds, and no precipitation. Wrap up travel plans if you can, clear drains and gutters of debris, and re-secure holiday decorations.
Tuesday to Thursday Evening: The next round of significant mountain snowfall may begin as early as Tuesday in northeastern California and the Sierra locations. Significant snowpack buildup probable for locations above 6,500 feet. Western Nevada and other areas below 6,500 feet will be dealing with periods of rain, snow and a wintry mix as snow levels fluctuate midweek.
Christmas Eve to Christmas Day: Another round of snow is probable for the holiday, with simulations leaning towards snow at all elevations. Yes, even down in Reno and Carson City. The lowest valleys below 4,500 feet may remain a rain/snow mix, but plan on a breezy and wet/snowy mess on roads region-wide.
Through the New Year: Simulations continue to highlight the potential for active weather through Christmas into the New Year for the Sierra and Western Nevada.
The weather service advises motorists to consider alternate routes or adjusting plans if traveling for the holidays. This is especially true for those heading into or out of the Sierra areas, where chain controls are likely to be in place.
Check the latest road conditions with Caltrans and NDOT. For Carson City area updates see CarsonWeather.com. The latest road conditions can be obtained by calling 511 for Nevada and 1-800-427-7623 for California. Monitor the latest weather forecast at weather.gov/reno and check road conditions routinely.
The latest weather discussion from the National Weather Service can be found here and below.
Strong surface inversions remain in place across the region through Monday morning as an expansive upper ridge responds with widespread subsidence locking in moisture and higher RHs (90-100%) for those Sierra and lower western NV valleys that have freezing fog and low stratus in their areas. Diurnal temperatures will range little in those Basin areas with fog and stratus.
Some locations may see highs at or below freezing dropping only a few degrees into the mid to low 20s overnight. Sierra and far western Nevada valleys, i.e., Truckee Meadows and Carson Valley, should see either partial or full fog burn-off by late morning. Hazy skies with some low stratus will be all that remains through the afternoon and evening. Lower basin valleys in western Nevada like Humboldt and Lahontan valleys could see only a partial burn-off by midday with widespread low stratus.
In advance of the next winter storm to affect the region, winds aloft over the Sierra ridges are still on track to increase later Sunday evening into Monday. The momentum and turbulence imparted over the complex terrain may be sufficient to mix out those Sierra valleys with fog/stratus, especially north of Mono County to Lassen and Plumas counties.
With the stronger inversions creating poor ventilation over those Sierra and lower western Nevada valleys that are fortunate enough to be fog and stratus free, some minor air quality issues and haze could arise. This is especially the case for more urbanized areas like Carson City and Reno.
Tuesday through Saturday, Christmas Day
Beneficial Snowpack Boost, but Detrimental Travel Headaches:
In the Sierra and for passes in northeast California, major travel disruptions, very long travel times, and possible periodic road closures are all probable.
— For the foothills and lower valleys of western NV- rain or a rain/snow mix Thursday. Snow levels drop more with increasing potential for travel disruption due to snow by Christmas Eve.
— This large upper low will be impacting much of the west, particularly California and Nevada, so stay up-to-date on the weather and road conditions if holiday travel takes you out of or into these regions.
Stormy weather pattern returns this week for northern CA and western NV on Tuesday. Simulations are closing in on a few time frames of wind/rain/snow that could create difficult travel conditions for the region. A large upper level low parks itself just off the CA coast for much of the week and will be the main culprit for the incoming inclement weather concerns.
Tuesday-Tuesday Night: Initial wave of moisture associated with a subtropical jet and an atmospheric river will sweep across much of California. Forcing and dynamics with this initial precipitation wave are still well offshore with the upper low, but orographic upslope flow paired with the moisture-laden atmospheric river should be enough to produce rain and snow for the west slopes of the Sierra, the Sierra crest, and possibly a bit of spillover onto the east side of the crest.
The position of the moisture and the jet would take aim primarily at areas from Tahoe southward, and with snow levels around 6,000 to 6,500 feet there is decent potential for accumulating snows in the Sierra. There may be periodic light rain/snow showers pushed into far western Nevada, but there is a lack of forcing to initiate spillover potential.
Wednesday through end of the week: It is difficult to discriminate distinct features from Wednesday onward, particularly in the deterministic datasets, as multiple waves appear to swing through the upper low. So rather than get caught up in that, let`s focus on where our probabilistic guidance can direct our attention. Simulations are showing signals for Thursday being a big storm day for much the Sierra and western Nevada. The moisture aligns with the upper ow, along with more significant forcing and jet dynamics to really kick off a long period of steady mountain snows, NE CA rain and snow, and periods of spillover into western Nevada.
High confidence for multiple feet of snow to areas above 7,000 feet, with a couple feet possible at Lake Tahoe level as well. Snow levels will be transitioning between Wednesday and Thursday so snow accumulations may be hard to come by for areas below 5,000 to 6,000 feet. By Friday, snow levels will likely be down near all valley floors, but areas below 5000 feet may still struggle to stack up some snow.
