Cooler temperatures will prevail over the coming days as additional rain and snow chances late week and into the weekend. Mountain snow with possible travel impacts mid to late week. Valley and foothill showers mid to late week. Brief lull between storms Friday afternoon with light snow accumulations. Slight chance for Valley thunderstorms Saturday afternoon
Discussion
Skies are clearing overhead tonight in the wake of yesterday’s storm system that brought snow the mountains, rain showers to parts of the Valley, and breezy conditions virtually everywhere. These clearing skies and decreasing winds are allowing temperatures to drop off quickly with efficient radiational cooling.
Widespread 30s to low 40s are likely in the Sacramento Valley by sunrise with a few locations around Redding falling near the freezing mark. Exactly how cold it will get is dependent on the wind — the calmer it is, the colder it will be. A Freeze Warning is in effect for the northern Sacramento Valley through 8 AM this morning.
Northwest flow will prevail overhead today, yielding to rather tranquil and seasonably chilly weather. Can’t rule out a few isolated showers in/around Shasta County, as well as portions of the northern Sierra Nevada.
Valley highs today will be in the low /mid-60s, or approximately 5 to 10 deg F below early/mid-April climatology.
Active weather returns through the end of the week as a series of systems take aim on northern California. Precipitation chances initially arrive later in the day Wednesday / Wednesday night as a shortwave trough ripples through the near-zonal flow.
Think that far northwest California (e.g., Humboldt, Del Norte Counties) will benefit most with precipitation through Thursday morning with lesser amounts in the lee of the Coastal Range.
Another shortwave will arrive to the northern California coast on Thursday, bringing another round of precipitation to the region late Thursday/Friday. Think that this round could bring a bit more precipitation to interior NorCal. Will note that there are still model/ensemble discrepancies, particularly with timing and placement, so confidence on rain/snow amounts remains low/medium. A more energetic frontal system will arrive for the weekend, see extended section for more details.
Extended Discussion (Saturday through Tuesday)
Wet weather continues through the first part of the extended forecast period as models in fairly good agreement with another Pacific frontal system making landfall Saturday.
Snow levels expected to be generally around 4500 to 5500 feet.
Drier weather forecast Sunday under EPAC upper ridging. Another frontal system progged into interior NorCal early next with some model differences at this time in timing and amount of associated precipitation.