Carson City area weather: Storm ahead, another Saturday to impact holiday travel

With the window for safe motor travel over the Sierra closing, the National Weather Service says travelers may experience headaches on their return home from the Thanksgiving holiday as another winter storm is brewing and likely to arrive by late Saturday into Sunday.

Cold temperatures will continue with this series of storms beginning Tuesday afternoon and extending into early Thursday. There will be some clearing Friday and early Saturday and then there's increased chance for more snow that would cause widespread travel impacts late Saturday through early next week, forecasters say.

The weather service notes that after a cold but relatively quiet period Friday into Saturday morning, the next winter storm will arrive Saturday afternoon. This storm is expected to bring snow to the Sierra, heavy at times by Saturday afternoon. Models show favorable for spillover, so about 6 hours after the snow starts in the Sierra, precipitation will then move into western Nevada if not sooner.

What the Weather Service knows now, is that significant snowfall in the Sierra with decent precipitation into Western Nevada. The precipitation will begin as all snow Saturday into Saturday night as models forecast a classic cold air damming setup. That means east winds at low levels will trap the cold air in the valleys. Water equivalent amounts could be anywhere from 2-5 inches along the Sierra Crest and up to 1 inch in western Nevada. Gusty ridge winds are also likely, with some gusty winds in the Sierra valleys. Winds in western Nevada will be low to moderate.

The weather service says what is not known at this point, is the precipitation type Sunday through Monday and therefore snowfall accumulations, especially for the valleys. Warm air aloft will move in with snow levels eventually rising to 6,000 to 7,000 feet by Monday night in the Sierra. However, with the cold air damming and cold air trapped, how long will it remain? It could be a situation where Lake Tahoe changes over to rain as much as 12 hours before Reno/Carson. Snowfall probability of 12-plus inches is 60-80 percent in the Sierra. For Reno and Carson City, the probability of 6-plus inches is around 50 percent.

Another concern, while very low probability but very high impact, is freezing rain mixing in with the warm air aloft. For valleys below 5,000 feet the weather service says there's a slight chance of freezing rain Sunday afternoon into Monday. More rain/snow with moderate snow levels into Tuesday.

Tuesday through Thursday
For the greater Lake Tahoe area and the Sierra, a Winter Storm Warning is in effect from 4 p.m. Tuesday to 4 p.m. Thursday. and 7 p.m. Tuesday to 7 p.m. Thursday for Mono County. Heavy snow is expected. Lengthy travel delays are likely, and it could take 2-3 times longer to reach your destination. Travel could be very difficult to impossible. Total snow accumulations in the Tahoe Area of 8 to 18 inches, except 1 to 2 feet expected above 7,000 feet are expected. In Mono County, 5 to 10 inches, except 10 to 24 inches west of US 395. Localized totals near 3 feet possible in both areas.

A Winter Weather Advisory is in effect from 4 p.m. Tuesday to 4 p.m. Wednesday for the Greater Reno, Carson City, and Carson Valley areas and 1 p.m. Tuesday to 4 p.m. Wednesday for Northern Washoe County. Travel could be very difficult as snow will accumulate at all elevations. Total snow accumulations of 1 to 5 inches, with locally higher totals expected south of US 50 due to possible lake-effect off Lake Tahoe Wednesday. For Northern Washoe County, 2 to 6 inches of snowfall is possible, with the highest totals expected north of Gerlach. Check the latest road conditions with Caltrans and NDOT or call 511. See NVRoads.com for the latest.