MEDIUM RANGE OUTLOOK
(weather trends through the next 6 to 10 days)
Despite the above headline, there is ample reason to believe that the nationwide mild spell (and that is what it is, national in context) is only a transient configuration. Consider that virtually all of the NWP schemes a vast pool of bitter cold (cAk) values across Canada and Greenland, while at the same time building a massive Rex signature across eastern Siberia. Since the colder regime is on the other side of the pole, the Russian positive height anomaly will not be able to tap into the full extent of the brutal temperatures. All of that cold air has to go somewhere, and teleconnections on the blocking high favor a corresponding ridge in the vicinity of YT and NT into SK....AB....BC after Day 7. When and if such a development occurs, it would pave the way for a strong intrusion of colder readings into the eastern two thirds of the U.S. But the operative question is WHEN.
The numerical models are routinely mild and inactive through the longer term, with the possible exception of the 0z Jan 4 ECMWF panels, which target CA with heavy rains again around 240 hours. The European scheme also seems to show a strong split flow (along the lines of that seen in a classic El Nino year), with the southern branch taking three impulses from CA to TX to FL and GA. This actually good news on two counts. One, enabling the lower Great Plains to get in on some tropical moisture (and possibly some rain), while at the same time starting to displace some of the Canada/Greenland cold dome into the lower 48 states, therefore lessening the boredom I feel in looking at these no-thrills computer forecasts!