A significant stratospheric warming event around January 5-7 will likely drop the Arctic Oscillation to very low levels starting around the 15th. Winter will come back in full force (see what's been going on in Europe for the past few weeks?) by the 20th. Any warmup until then should be unimpressive (near average), transient (in advance of a major cold front), or both. A Niño-esque Pineapple Express should provide ample moisture to much of the nation. Prospects are looking grim for the Niña warm-mongers (not naming names, but someone else's post a month ago said AO would be positive by now… instead there haven't been any positive readings in over a month, and it's very negative) to say the least.