Active weather pattern through Wednesday will keep numerous showers over the foothills and mountains and low elevation snow. A storm system late in the week will bring higher elevation snow raising the snow levels above the foothills. Increases on local creeks and rivers due to rain and snow melt mainly below 4000 feet.
Discussion
Large deep trough will remain along the coast through much of the week with several short-waves forecast to move across the region through mid-week. We’re currently in a relative break in shower activity with scattered snow showers continuing over the northern Sierra while the valley is dry. Snow levels remain very low, from around 1000 ft in Shasta County to 2500 ft across the Motherlode.
Snow will continue to rack up over the NorCal foothills and mountains into mid-week, though rates mostly won’t be as heavy as over the weekend, and precipitation will be more intermittent at times.
However, significant impacts to travel will persist. Additional snowfall totals of 1-3 ft can be expected in the Sierra over the next 48-60 hours with 12-18 inches across the northern mountains and some of the upper foothill elevations.
At the lower elevations, some snow may mix in at times across the far north end of the Sacramento Valley into early Wednesday, but accumulations will likely be minimal.
Occasional showers can be expected with a few late-day thunderstorms. QPF is forecast to be below half an inch.
A short break in precipitation will be possible late Wednesday into Thursday before the next storm moves in Thursday night.
Extended Discussion (Friday through Monday)
Next Pacific storm impacts the area late Thursday into Saturday. This system will be associated with a moderately strong AR, IVT above 500 kg/(ms). Snow levels will be on the rise Friday as warmer moist air is advected into interior NorCal. NBM progging them around 5000-6000 feet in the Shasta mountains, and 6500-8000 feet over the Southern Cascades and Northern Sierra Nevada by late Friday.
Precip turns showery Friday night into Saturday. Latest WPC QPF showing around 1-3 inches in the Central Valley, with 3 to 6 inches in the foothills and mountains.
Potential for significant snow melt in the lower elevations with possible hydrologic concerns.
Forecast confidence lowers Sunday into early next week as models diverge with timing of systems. Potential for more precipitation early next week.