Overnight weather models continue the trends that have been slowly appearing during the last few days in showing a colder pattern developing later next week. The European weather model has been particularly bullish on this idea. There is stronger support today coming from ensembles and other models but it is not roaring bullish by any means, at least not yet. There will be a question of whether the cold air holds for awhile. The European and GFS weather models seem to lean in this direction. Others or more transitory. Whether it is or isn't will depend on. As of this posting I don't have the new NAO/AO (North Atlantic/ Arctic Oscillation) forecasts but I'm assuming that based on the European weather model and other weather models that at the very least they are both trending colder for the Eastern United States.
All weather models show the the first shot of colder air arriving later next week. The European and the Canadian however do something that the GFS does not do and that it is they both either show or at least suggest that there is a second shot right behind it. READ MORE AT http://www.meteorologistjoecioffi.com/index.php/2016/12/22/weather-models-moving-toward-colder-pattern/