A strong Pacific storm system coming out of Alaska and Canada is expected to bring the first measurable rain and snow of the new water year to the Mother Lode next week, with chances of snow as low as 2,000 feet and lower in foothill communities of Calaveras and Tuolumne counties by Thanksgiving.

The chances for heavy rain and snow are highest Tuesday night into Wednesday next week, and its impacts are expected well south of Interstate 80, Emily Heller, a National Weather Service meteorologist in Sacramento, said Friday in a phone interview.

“Snow levels look to be pretty low, 2,000 to 2,500 feet for now,” Heller said. “Obviously this could change in the coming days as we get a better handle on the forecasts.”

There are also chances for gusting winds from 10 to 15 miles per hour for Sonora and Yosemite National Park on Monday. When the wet stuff is supposed to arrive, Tuesday to Thursday, 1 inch to 2 inches are expected in San Andreas, Angels Camp, Sonora and other foothill towns along Highway 49.

It remains to be seen how accurate current forecasts are for next week, whether rain and snow will come to Calaveras and Tuolumne counties, and whether they will continue into Thanksgiving Day and Black Friday.

Forecasters in Sacramento say the approaching system is bringing “potential for a high impact snowstorm Tuesday through Thanksgiving,” but as of Friday they were not guessing possible snow accumulation depths for Calaveras and Tuolumne counties.

If forecasts are correct, the approaching storm system will be the first to bring significant rain and snow to the Mother Lode’s principal watersheds since the current water year started Oct. 1. A five-station index that includes Calaveras Big Trees and Hetch Hetchy showed no measurable precipitation over the past seven-and-a-half weeks.

Calaveras and Tuolumne counties received 50 inches of precipitation in the 2018-2019 water year, less than 30 inches in 2017-2018, and 72.7 inches in 2016-2017, the second-wettest water year on record for watersheds including the Stanislaus River and Tuolumne River basins.


Contact Guy McCarthy at gmccarthy@uniondemocrat.com or 588-4585. Follow him on Twitter at @GuyMcCarthy.


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