The Pacific/North American teleconnection pattern (PNA) is one of the most recognized, influential climate patterns in the Northern Hemisphere mid-latitudes beyond the tropics. It consists of anomalies in the jet stream observed over the western and eastern United States.
Weather models indicate a significant transition to a strongly-negative PNA heading into the middle of the month of January.
During a negative PNA the jet stream is wavy, dipping further south than normal over the northwestern U.S. and unusually far north over the southeast.
This results in unusually-cold temperatures centered over the northwest and unusually-mild readings over the southeast.
And this is just what the extended outlook is indicating. It looks like a persistent pattern of colder-than-normal temperatures over the western half of the nation and unusually-mild weather over the east, especially the southeast.
January 11 – 16
There could be enhanced rainfall along the boundary separating these airmasses. This includes parts of the Southeast U.S., Ohio and Tennesse River Valleys.