Temperatures are a cooler Monday, and you'll likely need to keep your sweater handy. The coast will be in the 60s and inland in the upper 60s to low 70s.
A cold trough from the Gulf of Alaska is approaching the region and will likely fall apart just before it reaches us. There's a slim chance of light rain in northwestern San Luis Obispo County, and a chance of drizzle across the region as the trough interacts with the marine layer.
Weak ridging will move in by midweek, warming temperatures gradually. The marine layer will still be absent Tuesday in the wake of the cold front, but return in the overnight hours into Wednesday morning with a weak trough.
Another ridge will move in Wednesday night into Thursday, raising temperatures to near normal. However, high clouds will ride the back of the ridge Thursday afternoon with a series of troughs running from Friday through the weekend.
Temperatures will be much cooler Friday, but rain will mainly stay to the north of our region until Sunday night. There is a chance of widespread rain through Monday night with systems moving further south.