Tonight will be the coldest night since November of 2010. Places like Olympia will drop to 11 degrees, while Seatac remains one of the “warm” spots expected to plummet to 18 degrees overnight. We will start to dig our way out of this deep freeze tomorrow night as the Fraser outflow dies down. This will cut our artic air supply and start to slowly warm us up over the next few days.
Western Washington should return to the 40s for daytime highs by Tuesday. It will take a few days of pumping warm air (moisture) back into our extremely dry air (dew points in the single digits) to see rain back in the forecast. I expect that to happen by Thursday or so.