it's due to a transient feature that's causing it, though. I wouldn't expect that to happen, and once that ejects, you can get a huge storm. and if it shears, you probably get record cold. that pattern would certainly make the entire CONUS cold, it's just the GFS going off the rails a bit. highly doubt that happens
this kind of stuff happens the other way, too. I've seen anomalous 50/50 ULLs keep us at like -10 to -15 at 850 while the rest of the US is a blowtorch