With the first of a series of storms arriving overnight, the National Weather Service warns of a much stronger atmospheric river storm expected to arrive by the end of the week that will bring more valley rain to the Carson City area and western Nevada and heavy, wet snow to the Sierra Friday through early Sunday morning.
Heavy rain and high elevation snow is anticipated with this storm with peak rates Saturday and Saturday night.
Liquid totals in the Sierra could reach 5 to 7 inches over a 2-day period, with 2 to 4 inches in the foothills, and 1 to 2 inches across western Nevada, according to the weather service.
Snow levels are expected to rise to 8,000 to 8,500 feet for around 24 hours during the heaviest precipitation. Snow levels then begin to fall Saturday afternoon bringing impacts to most Sierra passes by evening and to Lake Tahoe and foothill elevations by early Sunday morning. The snow will be a heavy and wet Sierra cement, NWS forecasters said.
Forecasters anticipate there will be major rises on rivers, creeks, and streams. At this point, however, there is no mainstem river flooding expected. Urban and poor drainage problems may bring localized flood concerns. Travel will be difficult in the Sierra, especially those headed to Tahoe for New Year’s Eve activities.
Another round of gusty southwest winds are expected with this storm, but winds do not look to be as strong as those winds from Monday night and Tuesday morning.
Today through Thursday
Meanwhile, spillover rainfall will continue through Tuesday for western Nevada valleys with accumulations of 0.50-1.00 inch still expected. While some minor urban and poor drainage area flooding is likely during periods of high rainfall rates, mainstream river flooding is not anticipated but rises are expected.
Snow levels will lower through the morning with the colder phase of the storm moving in. Snow levels will drop to near 7,000 feet by mid-morning and near lake level by late this afternoon before dipping to around 5,000 feet this evening.
This will be the period where most widespread travel impacts are expected due to moderate to heavy snow. Elevations above 7000 feet could see 12-18″ of heavy/wet Sierra cement and up to 2 feet mainly along the Sierra crest, NWS forecasters said.
While western Nevada valleys will see mainly rain, a rain/snow mix will be possible on the valley floor Tuesday night with foothills potentially receiving a slushy few inches of snow.
After a general break in the weather Wednesday, a weak wave/warm advection will bring a round of light precipitation Thursday. Snow levels will be fairly low with some light snow down to about 4,500 to 5,000 feet. Snow accumulations will generally be limited to the Sierra passes above 6,500 feet during the daytime Thursday, but could result in some icy spots down to lake level and near the Oregon border from sundown through Thursday evening.
Snow showers will likely continue Thursday night as a very moist atmospheric river follows a secondary shortwave feature. Snow levels will be on the rise late Thursday night into Friday morning as the next significant system approaches.
