Dry and seasonable weather today ahead of another weather system occurring Wednesday into the weekend bringing periods of rain with isolated thunder chances, mountain snow, and breezy winds.
Discussion
Precipitation has tapered off with snow ending this evening. As a result, the Winter Weather Advisory over the Sierra has been allowed to expire. As the weather system exits the forecast, we will see a brief lull in active weather with dry weather today. We will see similar temperature highs today with highs in the upper 50s to mid 60s in the Valley with mid 30s to low 50s across the mountains to foothills.
The next weather system moves over Northern CA on Wednesday morning over the Coastal Range, spreading south and east from the Coastal Range. This will come in two waves with the initial wave (Wednesday – Thursday PM) being the heavier of the two. QPF totals will be 0.25-1.00″ in the Valley and adjacent foothills with 0.50-2.00″, up to 2.50″ over the mountains. 72-hour NBM probabilities for totals greater than an inch is 45-80% for Valley locations north of I-80, increasing as you move northward up the Valley. For mountain locations north of I-80, probabilities of amounts greater than 1.50″ is 75-90% chance.
Wednesday will see gusty south winds, strongest during the late morning and early afternoon hours. Gusts of 15-35 MPH forecasted with the highest Valley winds over the northeastern foothills and north-central Sacramento Valley. Along the Sierra, gusts of 20-45 MPH is expected, strongest along the peaks south of I-80. Winds begin to subside later that evening with lingering breezy winds over the mountains.
Thursday will bring isolated thunder chances (15-20%) across the Valley and adjacent foothills with highest chances across the northeastern foothills. With any thunderstorm, this brings chances for lightning, brief heavy rain showers, gusty winds, and small hail. If thunder roars, go indoors!
This weather system will also bring periods of mountain snow Wednesday morning through Friday evening. Snow levels will start around 4500-5000 feet on Wednesday, increasing throughout the day, and becoming 5500 to 6000 feet early Thursday morning. Snow levels drop again Thursday afternoon and settle at 4000-4500 feet by Friday morning. Snow total are forecasted to be 6 to 12 inches, locally up to 18 to 24 at the higher peaks above 5000 feet. NBM probability of amounts greater than 12″ is 65-90% chance for elevations above 6000 feet. For 2 feet, chances drop to 25-50% with the higher chances only existing over the Sierra Peaks and near Lassen National Park.
Rain will taper off in the Valley on Friday with lingering snow showers over the Sierra and Southern Cascades through Friday evening. Northern CA remains in active pattern after another brief lull in weather on Saturday with more rain and mountain snow incoming Sunday into early next week.
Extended Discussion (Sunday through Tuesday)
Upper ridging moves through interior NorCal early Sunday followed by another short wave trough Sunday night into Monday.
Widespread showers and mountain snow showers expected. Snow levels are forecast to be around 5000 to 6000 feet initially, lowering to 3000 to 4000 feet Monday morning. WPC advertising snow amounts up to around 7 inches. Liquid totals are up to around a tenth of an inch of rain in the Central Valley, highest in the N Sac Valley.
In the foothills and mountains, QPF ranges from a tenth to around half an inch. Drier weather expected Monday night into Tuesday as upper ridging builds inland. Some locally gusty north to east wind possible during this period into midweek.