April 12, 2018 – Cooler with a few showers today, especially over the mountains. Dry weather returns later in the week, but more rain and mountain snow is expected to return by Sunday into early next week.
Scattered snow showers continue over the Sierra even mixed with a few patches of freezing drizzle. Chain controls are still in effect for Interstate 80 and Highway 50 and will keep winter weather advisory going as another inch or two of snow is possible. Scattered showers will redevelop over the valleys this afternoon with instability from surface to 15,000 feet. Inversion at 15,000 feet should suppress thunder chances and have left that out of the forecast. Best afternoon shower chances will be over the North and Central Sacramento Valley.
Dry with a warming trend Friday and Saturday as upper ridge builds over NorCal. Temperatures for valleys will warm into the low and upper 70’s. The dry and warm conditions will be brief, as another cold and wet system drops south from the Gulf of Alaska. Current forecast shows best precip chances moving in Sunday afternoon and night with snow levels starting around 5500 feet falling to 4000 feet late Sunday night. Several inches of mountain snow are possible with this system and details will becoming clearer over the next few days.
Extended discussion (Monday through Thursday)
A long wave trough of low pressure will push through California Monday, which will bring rain across the valley and snow above 3500 feet. Upper level ridging returns Tuesday into Wednesday, resulting in dry and warmer conditions. This dry period will be short-lived as guidance indicates the next storm system moving across interior NorCal late next week. Specific details remain uncertain this far out. Stay tuned.