Cold for mid-late December?

Interesting paragraph in this afternoon's forecast discussion from Norman NWS:

BEYOND DAY 7... THICKNESS IN THE COLDEST POOL OF POLAR AIR HAS BEEN
IN THE LOW 470S OVER SIBERIA... IMPRESSIVE EVEN BY SIBERIAN
STANDARDS. GENERAL TRENDS OF THE GFS/ECMWF ARE TO SHIFT THE
COLDEST AIR MORE TOWARD THE N POLE AND EVENTUALLY TO THIS SIDE OF
IT IN 10 DAYS... WHILE MAINTAINING AN EVER-PRESENT POSITIVE HEIGHT
ANOMALY OVER THE N ATLANTIC AND AN UPSTREAM LONGWAVE TROUGH OVER
CENTRAL/EASTERN N AMERICA. CPC IS LEANING TOWARD RETROGRESSION OF
THE EASTERN TROF MORE TOWARD THE CENTRAL/SW CONUS DURING THE 6-10
AND 8-14 DAY PERIODS... WHICH SHOULD TELECONNECT TO CONTINUED
RIDGING FROM THE E PACIFIC N TOWARD ALASKA. WITH POLAR AIR
CONTINUING TO BUILD UP N... STAGE REMAINS SET TO CAUSE POSSIBLE
SIGNIFICANT AND WIDESPREAD WINTER-TYPE WX TROUBLE IN THE MID-LATE
DEC TIME FRAME... FROM EITHER A BIG-TIME ARCTIC INVASION AND/OR
SIGNIFICANT WINTER STORMS. FIGURING OUT THE DETAILS WILL REMAIN AN
EXERCISE IN FUTILITY AS LONG AS THE MED-RANGE MODELS STRUGGLE
WITH CONTINUITY.