First, let's talk about what has happened over the past month. During January and even a good chunk of December, the large-scale upper-level pattern featured a persistent high-amplitude ridge over western North America and the eastern north Pacific, with a persistent trough over the eastern United States. This can be seen in the departure from average (a.k.a. anomaly) of 500-mb heights for the past 30 days below.
This pattern appears to finally be shifting, with more progressive westerly flow pattern returning to the western United States. I don't have an equivalent graphic to the one above for the forecast period ahead, but below shows the departure of forecast 500-mb heights from the GFS for 0Z Feb 7th. Note that anomalously high heights (ridging) is shifted to over the Bering and Chukchi seas between Russia and Alaska, with anomalously low heights (toughing) over the western U.S.