Major Winter Storm impacting area through the weekend, bringing widespread precipitation, extremely heavy mountain snow with blizzard conditions, strong winds, and low elevation (1500-3000) snow accumulations. Additional snow accumulations through middle of next week.
- Today: Moderate to heavy snow continues over the Sierra this morning and afternoon, increasing to heavy snow (snowfall rates of 1-2 inches per hour) with the next push of moisture late afternoon through early Sunday. Snow levels around 3000′ today. Isolated Valley/foothills showers this morning become more widespread this afternoon and evening, with another round of isolated thunderstorms possible as well. Winds remain gusty (30-40 mph) across the foothills and mountains, but generally decrease throughout the day.
- Sunday: Heaviest snowfall expected early Sunday morning, before tapering off to more Moderate snowfall throughout the day, and light snow showers through the evening. Snow levels 1500′-2500′ Sunday morning, rising to 2000′-3000′ throughout the day. A few isolated rain showers may linger in the Valley, but minimal impact is expected. Breezy south-southwesterly winds persist, with gusts to 35 mph over the mountains.
- Monday-Wednesday: Some lingering light snow showers will likely prevail over the mountains early Monday, but otherwise a brief lull in activity is expected. The next system arrives later in the day on Monday, bringing increasing precipitation impacts by Monday afternoon. Moderate to occasionally heavy snow (snowfall rates of 1+” per hour at times) is expected over the mountains, with heaviest snowfall anticipated Monday evening through Tuesday. Forecast snow levels are expected to be around 2000′-3000′ on Monday, rising to 3000′-4000′ Tuesday into Wednesday. As a result, some upper foothills accumulating snow will be possible on Monday. Elsewhere, precipitation impacts from isolated to scattered showers will be minimal, with wind being the primary impact on Monday. South-southeasterly winds gusting 30-40 mph will be possible on Monday, strongest across the foothills, mountains, and northern Sacramento Valley. Precipitation then generally begins to taper off, with mostly lingering mountain snow showers expected on Wednesday.
Bands of showers along the slow moving cold front continue to feed up into the northern Sierra early this morning resulting in blizzard conditions.
Upslope and convective enhancement (occasional lightning flashes) is resulting in snowfall rates of 2-4 inches or more per hour, and numerous observing sites are still reporting gusts of 40-70 mph across the higher elevations.
Interstate 80 remains closed east of Sacramento to the Nevada stateline. The worst of the blizzard conditions over the northern Sierra are expected to ease this morning as the front shifts further south and weakens, however the major winter storm with severe impacts will linger into Sunday.
Elsewhere, snow levels lowering to 1000-1500 ft over the northern mountains will bring some accumulating snow down to the fringes of the northern Sacramento Valley over the next 24 hours. The north-south surface pressure gradient is easing, and the wind advisories for the Central Valley will expire/cancelled by 4 AM. It will remain breezy today in the valley with gusts of 25-35 mph.
Additional snowfall is likely after the warnings have ended Sunday morning into early next week. We remain in west-northwesterly flow which will allow moisture to continue to move into the area.
Most of the impacts will be felt in the Sierra, Southern Cascades, Coast Range, and the Foothills, with limited Valley rainfall thanks to shadowing.
Snow levels on Monday should climb back to around 2500 feet in the morning, then around 3500-4500 feet Monday evening. Additional snowfall may hamper blizzard recoveries.
Mountain travel is HIGHLY discouraged while the warnings are in effect!
Extended Discussion (Wednesday through Saturday)
Model differences with placement of upper low off the CA coast Wednesday, but all show it digging to the SE and opening to trough as it moves inland over Baja. This will result in a chance of light showers Wednesday, mainly over the mountains. Drier weather follows Thursday through Friday as upper ridging in EPAC builds inland.
Warming temperatures expected with near normal highs by Friday. Some locally gusty north to east wind will be possible Thursday. NBM/GFS more progressive with upper ridge, and prog another short wave trough with associated light to moderate precip over interior NorCal Saturday.