Depending on how far south an approaching storm system tracks, Mother Lode residents could see more rain and snow Tuesday night and Wednesday, with snow levels down to 3,000 feet or lower.
Twain Harte is about 3,650 feet, and Mi-Wuk Village is about 4,675 feet. Lower down, Soulsbyville is about 2,900 feet, and Sonora’s elevation is listed on many maps as 1,785 feet above sea level.
If forecasts are accurate, the approaching storm system could bring 0.10 inch to 0.25 inch of rain to Sonora and other foothill towns along the Highway 49 corridor, forecasters say.
Snow forecasts for higher elevations include 3 to 4 inches possible for Carson Pass on Highway 88 and Ebbetts Pass on Highway 4, 2 to 3 inches for Sonora Pass on Highway 108, and 1 to 2 inches for Tioga Pass on Highway 120. Carson Pass remained open Monday. Ebbetts, Sonora and Tioga passes are closed for the winter.
Forecasters say their confidence is high for their predictions of rain and snow accumulations, but it’s medium for snow elevation levels. They also think most of this storm system’s rain and snow is expected to fall north of Calaveras and Tuolumne counties.
Jim Mathews, a National Weather Service meteorologist in Sacramento, said Monday in a phone interview, “We expect some precipitation in Calaveras and Tuolumne counties, but not as much as north of Highway 50.”
For Sonora and other foothill towns on Tuesday, residents can expect it to be mostly sunny with daytime highs in the 60s, followed by rain showers moving in Tuesday night and overnight lows in the 40s.
Strong rain chances are expected to continue Wednesday morning in foothill towns, decreasing in the afternoon with daytime highs in the 50s. Clear weather is expected to move in Wednesday night with overnight lows dropping to freezing at about 32 degrees.
Thursday and Friday are expected to be sunny and clear with daytime highs in the 50s for Sonora and other foothill towns, and overnight lows in the mid-30s.
Wind gusts of 50 miles per hour and higher will be possible on exposed ridges in the mountains on the westside Central Sierra. There’s potential for hurricane-strength gusts at the highest elevations to the east.
Forecasters in Reno have put out a high wind watch for the eastern Sierra for Tuesday evening through Wednesday morning. They are advising there could be gusts of 120 miles per hour along the Central Sierra crest, which includes the highest, east edges of Calaveras and Tuolumne counties, and the east edges of Yosemite National Park.
“Some disruption to air travel and high profile vehicles should be expected,” forecasters in Reno said in a statement Monday. “Now is the time to secure loose outdoor items such as patio furniture, holiday decorations, and trash cans before winds increase, which could blow these items away. The best thing to do is prepare ahead of time by making sure you have extra food and water on hand, flashlights with spare batteries and/or candles in the event of a power outage.”
Forecasters are calling the approaching system a fast-moving one, but that remains to be seen.
The current water year started Oct. 1 and it’s been comparatively dry so far in major Central Sierra watersheds. From Calaveras Big Trees in the Stanislaus to Hetch Hetchy in the Tuolumne and Yosemite Valley on the Merced, 4.8 inches of precipitation have been measured so far this wet season.
That’s 46 percent of the average for the date Dec. 18. It’s also more than 10 inches less precipitation than the same area received through Dec. 18 last year, when the 2016-17 winter was the second-wettest on record, and about 4 inches less through the same date in the 2014-15 water year, one of the driest on record.