Above is the GFS Ensemble 500 millibar height anomaly forecast for February 10th. We can see low pressure in the Southwest US, as well as high pressure stacked on top of it in the Pacific Northwest and Southwest Canadian regions. This stacking formation is an atmospheric blocking pattern called the Rex Block. When the Rex Block sets up, you have two centers of low pressure and high pressure that are essentially not moving unless the other does. As a result of Rex Blocks that form on the West Coast, one tends to find high pressure and zonally-oriented (plain west-to-east wind flow, no cold shots pushing south) wind flow. This is exhibited well in the forecast image above, where you can see strong high pressure in the East US as a byproduct of not only the solid Rex Block, but also due to the deep trough in the Bering Sea. This trough of low pressure means an index called the West Pacific Oscillation is positive. The positive WPO brings about low pressure in the Bering Sea and high pressure (and warm temperatures) in the East US.
This is certainly bound to change, and I will update when it does. This is a look at what could happen come Valentine's Day.