Forecasters at the National Weather Service office in Reno are warning that a major winter storm today and Tuesday will bring multiple rounds of snow at all elevations, along with gusty winds that will produce blowing snow and localized blizzard conditions across the Sierra.
Anticipate widespread travel impacts across the region, especially in the Sierra. A colder airmass will result in sub-zero wind chills across the Sierra through Wednesday.
Blizzard Warnings are in effect for the Sierra starting this morning.
A Winter Storm Warning and Winter Weather Advisories have been posted for western Nevada areas Monday through Tuesday night.
Expect periods of gusty southwest winds today through Tuesday which could lead to blowing snow with reduced visibility at times with whiteout conditions possible across the Sierra.
According to forecasters at the National Weather Service this powerful Pacific winter system will bring a potpourri of significant winter impacts to the Sierra and western Nevada through Tuesday with unseasonably colder temperatures by Wednesday.
The upper system driving into the Pacific Northwest will setup a volatile mix of colder, more moist maritime air, stronger mid-level winds, instability, and increased dynamic forcing from the exit region of a 150kt jet core.
Periods of heavy snow and gusty winds will bring near zero visibility due to blowing snow to many parts of the Sierra through Tuesday. This combination of significant weather will make travel over mountain passes hazardous if not near impossible starting late this morning across Northeast CA west of US-395, which will work southeastward into the Sierra Front, Lake Tahoe Basin, and then into the eastern Sierra-Mono county Monday afternoon through Tuesday evening.
An initial cold front and followup colder secondary wave will bring a double shot of heavy snow across the Sierra with the first salvo this afternoon and evening, that repeats again late Tuesday morning into Tuesday evening. There is a high chance (70-80%) of significant snowfall of upwards of 4 to 6 feet across the Sierra crest with 2 to 4 feet for communities in and around the Lake Tahoe Basin, and eastern Sierra west of US-395 in Mono County.
During the periods of heavier snowfall, snowfall rates could still exceed 2-3″/hr for a time during these more intense accumulation periods. The colder nature of this storm will bring a lighter/fluffier variety of snow consistent with the with 15:1 snow ratios. This snow could be easily ablated with winds gusting 50 mph or more across Sierra communities with much
worse conditions across Sierra ridge tops where wind gusts could briefly exceed 100 mph.
Two periods of snow spillover into western Nevada will coincide with passage of both fronts moving through the region. The first period will occur overnight tonight with a brief wintry mix of rain-snow starting at valley floors changing to mostly snow into the evening.
At least 1-3 inches of accumulating snow will be confined to front lawns and more open areas with area roads receiving a slushy mess up to a couple inches after the full change-over to snow.
The follow-up secondary wave will spill into western Nevada Tuesday afternoon, bringing colder air with increased chances (50-60%) of several more inches of accumulating snow to valley floors with foothill areas above 5,000 feet seeing up to a foot of new snow. Areas across the west-central Basin and Range including Pershing, Churchill, and Mineral counties will see a moderate chance (30-40%) of lighter snowfall amounts of up to a couple inches with this second wave.
It cannot be reiterated more to expect widespread travel impacts during these two distinct periods of heavy snow. Travel over Sierra passes could become quickly treacherous and dangerous with blizzard conditions forecast for the region. Travel across western Nevada will also be troublesome as higher snow accumulations coupled will gusty surface winds will make travel across the region that much more challenging.
Snow showers will linger across the region as some instability attends a core of colder air with the exiting upper trough. The increasing northerly upper flow, however, will maintain below average temperatures across the Sierra and the Great Basin region in general through the latter half of the week into the weekend. Therefore, expect to see lighter winds and quieter weather through the balance of the week. But, wait a minute. Ensemble guidance is growling up a roar into next weekend as another less potent winter system ushers in what looks to be the continuance of an active weather pattern into next week.
