As wind continues to be a factor for Carson City and surrounding counties, heavy rain and the threat of localized flooding along with snow in the Sierra are among the concerns as we move into the Christmas holiday travel window.
Significant rain and high elevation snow continues to stream across northern California, along with gusty winds. Areas of heavy precipitation have been noted from I-80 and points northward, which prompted the National Weather Service to issue a Flood Watch for Lake Tahoe and northeastern California now through Monday afternoon.
The Flood Watch areas include the Greater Lake Tahoe area and the West Fork of the Carson River near Woodfords as well as Lassen, Eastern Plumas and Eastern Sierra counties, which includes the Susan River near Susanville.
Wind
Windy conditions continued Sunday with a High Wind Warning that remains in effect until 4 a.m. Monday for Carson City, Carson Valley, Washoe Valley, Reno, Virginia City and along the western Nevada foothills. There’s also a Wind Advisory for the Lake Tahoe Basin that extends through Monday morning.
Snow
A Winter Weather Advisory for the Lake Tahoe Basin is in effect from Sunday afternoon to 1 p.m. Monday, while a Winter Storm Watch for the Lake Tahoe Basin and west slope of the Sierra will ride on the advisory’s tail through at least Christmas day and Friday morning.
At this time, early Tuesday will offer the best window for a break in the weather, forecasters said. While there will still be showers along the western slopes of the Sierra, the eastern side may not see that much. However, late Tuesday will see the Atmospheric River oscillate north to south along the Sierra, bringing spillover that will hold off until it settles over Mono County and begins to push over the mountain range.
Once the atmospheric river takes hold, forecasters say snowfall along the higher portions of the Sierra could be heavy and bring significant amounts through Christmas. Forecasters say it will depend on how cold it gets as to how much snow piles up in the lower portions of the Sierra.
For now, forecasters say accumulations of 12-18 inches are possible in the Tahoe Basin above 8,000 feet with snow accumulations of 18-24 inches in Mono County, Calif. above 8,500 feet.
As for snowfall for Carson City and lower valley areas, Wednesday, Christmas Eve, forecasters are saying there is anywhere from a 90 to 100 percent chance of a rain/snow mix in time for Christmas. Will it be a “White Christmas in Carson City? Stay tuned.
Here’s what NWS forecasters wrote in their latest forecast weather discussion:
Snow levels overnight Tuesday into Wednesday will start out above 7500 feet, abruptly tumbling as Tuesday turns to Wednesday. By midday Wednesday, snow levels will be tumbling to below 6,000 feet to near 5,500 feet by Thursday morning. So if you are wondering whether you will have a White Christmas (1 inch on the ground by 7 a.m. Christmas morning), you will have a better opportunity above 6,000 feet. However, if you wait until late Thursday night, you are more likely to see measurable snow. The Tahoe Basin has a 20-30 percent chance for gathering 6 inches of fresh snow by Christmas morning, while our friends in Mono County have a 70 to 80 percent chance of 6 inches by 7 a.m. Thursday. The foothills including Virginia City have a 10 to 20 percent chance for 6 inches of new snow by Thursday morning.
But that will not be the end of the snowfall, as the bulk of the snow will arrive for the day Thursday. Travel across the Sierra will be difficult to impossible at times, with lower elevations getting in on the action late Thursday as snow levels continue to fall.
Travel
The colder Atmospheric River system will bring strong winds with heavy rain and snow as early as late Tuesday and continuing through at least Christmas Day. Snow levels are lower (5,500 to 7,000 feet) bringing increased chances for widespread impacts, including travel delays. Forecasters say there’s a “non-zero chance” for a White Christmas for much of the Sierra.
Travel over the Sierra could be very difficult to impossible, NWS forecasters warn. The hazardous conditions could impact holiday travel plans and morning and evening commutes. The combination of strong winds and the weight of heavy snow accumulations could damage trees and power lines.
For the latest travel conditions see NVroads.com and Caltrans here.
Check back for updates.
