But all will change this week, as a significant shift in the large-scale flow pattern will bring moist, warm southwesterly flow to our region, accompanied by substantial rain in the mountains.
Tonight a ridge of high pressure sits over the West Coast (see map of 500 hPa heights and winds at 8 PM). It won't last.
By Wednesday at 11 PM, the ridge has deamplified and southwesterly flow will be over us. Expect showers on that day.
A ridge rebuilds temporarily on Thursday afternoon (5 PM shown)
If you were losing sleep because you were worried about filling Seattle's reservoirs, stop worrying. If you were losing sleep because of concerns about snow conditions for skiing, get a tranquilizer.
You want to know how much rain? Well, here is the 48h total amount ending 5 PM Thursday. A modest amount, but useful, particular since the high Olympics could get a few inches.
On the other hand, the 48h totals ending 5 PM Sunday will be enough to make old Pluvius proud, with several inches in all of mountains, 3-4 inches in the north Cascades, with lots of precipitation falling into the watershed of the Columbia River. Good for irrigation, fish, and power. Even parched northern California will get a piece of this.