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This is Marvin Boyd from the National Weather Service in Reno with an update on the series
of winter storms that will impact the Sierra and western Nevada Friday afternoon through
Monday morning. This short briefing will get you up to speed
on what we expect over the coming 3-4 days as an atmospheric river brings a variety of
winter weather to the region.
Heavy snows are likely in the high Sierra – especially above 8000 feet, periods of
snow and some rain at lower elevations in the Sierra and in western Nevada, and strong
downslope winds are possible in the immediate lee of the Sierra including Reno, Carson City,
and Mono County.
I want to emphasize that our forecast confidence isn’t the highest with this series of storms
– there’s been a lot of variability in our computer model projections of these storms
so our forecasts are likely to change over the coming day or two. Now – let’s get
into the details of what we know. You may want to maximize this video on your screen
to see the detailed maps coming up. Given increased travel around the area at
the end of the week – this is part of the forecast everyone should keep an eye on. Conditions
over Sierra passes are expected to be very poor due with significant travel delays becoming
likely as snow rates increase Friday evening.
The next wave will bring moisture onshore out of the Pacific and into the Sierra late
Friday afternoon through early Saturday morning. Snow levels begin rather low on Friday ranging
from 5000 to 6000 feet after Thursday’s first round of snow showers. Totals fall from
near the crest around 24 inches to around 6 inches for Sierra valleys. There will be
very limited spillover into western Nevada with this round as higher level winds are
not the most favorable – still up to 2 inches will be possible mainly above 5000 feet.
Winds along the Sierra front may gust up to 60 mph. This will especially be true where
precipitation is more shadowed from southern Washoe County to Mono County.
Here are the updated graphics showing forecasted snow fall on the left and wind gust potential
on the right. As noted on the previous slide, snow totals will be highest along the Sierra
Crest with lighter totals towards the Sierra front. Winds will also gust up to 60 mph along
the Sierra front mainly from the Galena area to Mono County along and west of Highway 395.
Here’s where the main heavy rain/snow event is expected – from Saturday afternoon into
early Monday morning. Confidence is a bit better with this part of the forecast as most
of our computer model projections show an atmospheric river impacting the Sierra and
producing heavy precipitation. Snow levels continue to have higher uncertainty, but there
is a clearer picture today than yesterday.
Right now we feel that snow levels will start off low just above valley floor elevations
in the 5000 to 6000 foot range, rise rapidly to 7500-8500 feet later Saturday and into
Sunday, and then fall to near 6000 feet as the storm exits Monday morning. The storm
track continues to suggest that areas from Bridgeport northward have the best shot at
heavy snows – but some localized totals in Mono County could be significant as well.
There is potential for a couple feet of snow above 8000 feet, but accumulations below 8000
feet are more uncertain due to large variations in the snow level as it wavers about 1000
feet depending on precipitation rates.
Valley areas east of Hwy 395 may pick up a quarter to half-inch of rain, mainly on Sunday
as winds aloft become strong enough to push moisture off the crest.
Here’s a look at the total precipitation from Friday through Monday morning. Snow totals
are on the left and liquid equivalents on the right.
So that concludes our briefing on this upcoming series of storms. I again want to emphasize
that, although forecast confidence has increased, it is still medium – and that forecast details
are likely to change over the next 1-2 days. Keep checking our website at weather.gov/reno,
and our social media feeds, for updates.
Anyone with travel plans Friday through Monday morning, especially those going through the
Sierra, will want to prepare for winter driving conditions and allow plenty of extra time
for travel. Thanks for listening and we’ll talk again soon.