GFS said it would be snowing here this morning a few days ago. Currently it’s 40F and raining.

Got to be ready for those February 70 burgers. Not too familiar with your location, but do you get downsloping in any of our winter patterns? Is it enough to enjoy a Mai Tai?

That’s an artifact of cooling just above the ice sheet. It is not a 500mb/pattern feature, unfortunately (note your map plots 1000-500mb thickness, which is the vertical distance between the 1000mb and 500mb layers). In terms of 500mb geopotential height anomalies, it is a relatively mundane pattern.

Unfortunately if this ridge gets squashed instead of retrogrades an AR will probably happen.

Your best bet is to follow the Euro/EPS and GEM/GEPS with GEFS as supplementary. Ignore the operational GFS entirely. It is next to useless.