Storms expected Christmas day and throughout the weekend
Parts of the Mother Lode could be in for a white Christmas as a pair of storms are expected to bring more rain and snow starting Friday.
There is a winter storm watch in effect from 10 a.m. Friday to 10 a.m. Saturday for Twain Harte and other towns farther east along the Highway 108 corridor, as well as Avery, Arnold and Calaveras Big Trees on the Highway 4 corridor.
A winter storm watch means there is potential for significant snow, sleet or ice accumulations that may significantly impact travelers. Snow levels on Christmas Day could fall as low as 4,000 feet.
The second storm is expected late Sunday and Monday, though the first storm appears to be the stronger and wetter of the two and has more potential for mountain snow, Hannah Chandler-cooley, a National Weather Service meteorologist in Sacramento, said Wednesday.
Chandler-cooley said the first storm is coming out of the Gulf of Alaska and the Pacific Ocean off the West Coast, where it will tap into Pacific moisture before coming ashore.
“It’s cold moisture,” said Robert Baruffaldi, another NWS meteorologist in Sacramento. “It’s not a pineapple express. It’s an atmospheric river, not a strong one. It’s an average winter storm for us. It may be tapping into moisture from the west and southwest. That could include some subtropical moisture.”
Baruffaldi said the storm expected Sunday into Monday is moving a little slower and may bring more rain and snow.
The first storm Friday into Saturday could bring as much as 1 to 2 inches of rain to So
nora and other foothill towns; a half-inch to 1 inch of rain to Yosemite Valley; 12 to 18 inches of snow at Ebbetts Pass; 8 to 12 inches of snow at Sonora Pass; and 6 to 8 inches of snow at Tioga Pass. The mountain passes on highways 4, 108, and 120 are closed for winter.
Tuolumne County locations that could see a white Christmas with fresh, falling snow on Friday include Long Barn, Strawberry, Pinecrest and Dodge Ridge.
Communities at lower elevations, including Mi-wuk Village, Twain Harte, Soulsbyville and East Sonora, and Arnold and Murphys in Calaveras County, may or may not get snow on Christmas Day.
An additional threequarters of an inch to 1 inch of rain is possible Sunday into Monday for Sonora and Yosemite Valley.
Snow levels with the second storm could fall as low as 2,500 feet. Forecast confidence in precipitation amounts for the second storm is lower, and it currently looks weaker than the Friday-saturday storm, forecasters said Wednesday.
Foothills residents can expect Christmas morning lows in the mid-30s, then mostly cloudy with a high in the mid-50s, and rain likely in the afternoon on Christmas Day.
As of Wednesday afternoon, a five-station index that includes Calaveras Big Trees, Hetch Hetchy and the upper Stanislaus and Tuolumne river watersheds showed 3.8 inches of precipitation since the current water year started Oct. 1, equivalent to 33 percent of average for the date Dec. 23.