A large polar airmass is sagging south across the Central US today, bringing with it decently below average temperatures juxtaposed against the above-average temperatures currently along the Gulf coast and the Eastern Seaboard.
That's a fairly strong gradient in the 850 hPa temperatures running from the Texas panhandle up through the Kansas City area and towards the east-northeast. This setup with cold air surging east of the Rockies as easterly flow runs up against the foothills and is forced south is a typical look for cold air outbreaks across central CONUS.
Taking a cross section across this temperature gradient, we can see an impressive vertical gradient in theta-e, with characteristically high static stability within the frontal zone.
Just looking along the 850 hPa level, there's probably about a 1K/10km theta-e gradient along that transect. Thermal wind balance tells us that where there's strong horizontal temperature gradients, there's bound to be strong cross-gradient shear, and sure enough, check out the magnitude of those winds normal to that transect!
That's a tremendously large expanse of strong westerlies aloft, but that's just about what we'd expect given the sagging cold airmass that's producing behind strong meridional temperature gradients. Both the polar and subtropical jet cores are evident here. That subtropical jet is really high up, straddling the tropopause region and maybe even poking in the stratosphere. Models indicate intensification of that jet, which should deposit energy downstream and result in an zonally-extending jet core across the Pacific, as we see depicted on the GFS:
With how strong that jet core is, that signals oodles of synoptically-forced ascent in the left exit region over the North Atlantic west of the British Isles. This entire portion of the jet will take about a week to propagate past the Atlantic, so there could be several days of repeated cyclonic development over the North Atlantic with tracks into Western Europe. That could result in a prolonged period of onshore flow with significant fetch which could lead to very high waves in the Bay of Biscay and surrounding environs:
