Colder, then warmer

Here is a plot of the observed 1000-850 mb thickness for the past few days (blue) and the forecast from the GFS for the next few days (red). Thickness is a measure of the mean temperature of a layer of air, in this case roughly the lowest 4500 feet. From this I would expect tonight will be the coldest night in the area. Temperatures will start to rise in earnest during the day Monday, and in the hills will probably be rising steadily for a couple days. Nighttime valley temperatures will depend in part on when clouds move in.