Light snow possible around Carson City by Christmas, travel impacts likely over Sierra

Winter weather will arrive in time for Christmas with a good chance of rain turning to light snow Monday night into Christmas morning around Carson City and valley areas and a solid chance for snow accumulation in the Sierra, according to the National Weather Service.

A Winter Weather Advisory is in effect from 10 a.m. Monday to 7 a.m. Tuesday for Lake Tahoe and Sierra. Total snow accumulations of 1 to 5 inches below 7,000 feet is expected with 6 to 15 inches above 7,000 feet and winds gusting as high as 60 mph over Sierra ridges. The best time for holiday travel is now through Monday morning, weather forecasters advise.

For the Sierra, snow levels will start around 6,500-7,000 feet Monday afternoon, rapidly falling to below 5,500 feet behind a cold front Monday evening. Travel could be very difficult. The hazardous conditions could impact the morning or evening commute.

A Winter Weather Advisory for snow means periods of snow will cause primarily travel difficulties. Expect snow covered roads and limited visibilities. The latest road conditions can be found at NVRoads.com or calling 511.

By Sierra standards, this is not a major storm, with 6-15 inches likely for areas above 7,000 feet, but the increased holiday traffic will likely compound the impacts, according to the weather service. The snow will start off as heavy and wet before transitioning to light and powdery.

NWS weather models have come into better agreement in the timing of the cold frontal passage, with Monday evening looking likely for NE CA and the northern Sierra, between 8 p.m. and midnight for the greater Reno and Carson City metro areas into the Central NV Basin and Range, and between 10 p.m. and 2 a.m. for Mono and Mineral counties.

Still, the biggest boom or bust potential in the forecast is snow amounts in the 5,500 to 6,500 foot range, where totals could range from an inch or two up to six inches. Decent mixing during the day Monday will boost high temperatures, and models have been trending upward on snow levels for the daytime hours, forecasters say.

Snow levels quickly fall behind the cold front, but the question is the timing of the moisture in relation to snow levels falling. Several models are showing a burst of heavier precipitation rates with the front, which in itself could drag snow levels down faster.

Most of the precipitation will fall as rain across western Nevada, but light snow along and behind the cold front is not out of the question. Minor accumulations are possible, especially given the snow will fall overnight, though the weather services advises that it won't be much, likely an inch or less. Higher elevation sites such as the Virginia City Highlands into Virginia City itself could see 1-2 inches of snow overnight into Christmas morning.

In addition to the rain and snow, winds will increase late in the day Christmas Eve into the night, with peak speeds reaching 35-45 mph in valley locations. For many, this is not as strong as the couple of wind events the area experienced this past week, but still strong enough to blow down any unsecured holiday decorations.

Cold temperatures and lingering snow showers will persist through Christmas Day with northerly winds making it feel even colder. The cold northerly flow across the relatively warmer lake waters could produce lake enhanced snow showers downwind, south to southeast of Pyramid Lake. Winds will be shifting from north to east over Lake Tahoe, so the deeper unidirectional flow needed for lake enhancement is less likely to set up.

Forecasters say Thursday and Friday there may be increased cloud cover and added slight chances of snow showers across more portions of our region. Overall, NWS forecaster say expect a few days of brisk and chilly conditions between Christmas and New Year`s Eve.