Light mountain showers and chilly morning temperatures to ring in the new year. Another system approaches late week bringing widespread precipitation, light mountain snow, and chances for Valley thunderstorms.
Discussion
Happy New Year from all of us here at NWS Sacramento! RADAR at 1:30am is showing some light precipitation progressing eastward towards Shasta County, though as of yet, only the coastal foothills have seen any measurable rain tonight. Any precipitation that falls during the rest of today will be low impact, with generally a quarter inch or less expected in the northern Sacramento Valley, foothills, and mountains over the course of the day. Isolated sprinkles in the remainder of the Valley also cannot be ruled out. Thursday will be dry through the afternoon, then more widespread precipitation returns in the evening.
Ensembles are still depicting a fast-moving trough progressing through northern California starting late Thursday and continuing through Friday. The majority of precipitation will occur over the northern Sacramento Valley, foothills, and mountains, with the NBM showing a 40 to 70% probability of at least 0.5 inches of rain in those locations. Elsewhere in the Valley, there is a 30 to 60% chance of at least 0.25 inches of rain.
Given the general warming trend we’ll experience through Thursday, snow levels are still expected to start fairly high above pass level (around 8000 to 9000 ft), before lowering over the course of Friday to around 5500 to 6500 ft in the evening. Above 6000 ft, the NBM has a 20 to 50% chance of 4 inches of snow or more. Snow showers may linger into early Saturday morning, but totals from any lingering showers will be minimal.
Isolated thunderstorm chances for Friday afternoon and evening have decreased to around 10%, though a stray storm in the Valley cannot be ruled out still.
Saturday, as the aforementioned system ejects to the east, upper level ridging will begin to set in again, ushering in another period of drier, generally calmer weather.
Extended Discussion (Sunday through Wednesday)
Upper ridging in EPAC extends inland over interior NorCal through the extended forecast period. Dry weather expected with areas of of gusty north to east wind at times. High temperatures forecast to be near to slightly above normal through the extended period.