2. Snowstorms around North Bend, Roseburg, Grants Pass, and Medford.
These 500 Mb configurations are always the coldest setup for the entire region of Washington, Oregon, and sometimes much of California. Almost non existent southern branch pinching off the blocking ridge.
Allows offshore surface wind flow to the coastline of Southern Oregon and Northern California.
Tends to leave Washington and northern half of Oregon drier than other covered tiers in my blog. While southern coast, Eugene/Corvallis, and south experience significant winter storms, as sliders form on the lee side of the ridge, pick up moisture over the Pacific, and then swing inland.
Not the configuration the northern half of Oregon and Washington want if you're looking for big snowstorms such as Jan 10-11 2017, Dec 2008, Feb 14 1995, or Feb 19 1993. All those snowstorms occurred with edge of cold air dome a further north and east, leaving at least Roseburg, North Bend, and even Eugene in the warm sector.
The transition out of these cold periods is usually when other areas of the region join in on the winter storms which were dry through much of the episode.
Dec 7 2009
