I like to keep my seasonal forecasting short and sweet, so here it is:
– Latest model guidance and ENSO trends suggest DJF will likely be a weak El Nino.
– +PDO to support ridging in the western U.S. and troughing over the Midwest/eastern U.S.
– +AMO could help keep the Southeast milder (read: less cold).
– -QBO will allow for a greater chance for blocking in the Atlantic (-AO/-NAO) as well as stratospheric warming events. This would promote colder temperatures in the eastern half of the country.
– Drought conditions in the West will promote warmer and drier conditions there.
– The western U.S. could go warmer given favorable +PDO and long term drought.
– If -NAO/-AO becomes the main forcing mechanism for the U.S. weather pattern, it could bring colder air into the Midwest, Mid-Atlantic and Southeast while providing warm and wet risks in New England.
– If a moderate Nino develops, a stronger subtropical jet associated with it could allow for wetter conditions across the southern U.S. and Mid-Atlantic.
A note on my track record… I have been about 50/50 with long-range forecast skill since I started in 2010. There are many others out there with more long-range knowledge, reasoning and a better understanding of how the atmosphere works on a longer timescale. That said, nearly every forecast I have seen so far favors a warmer West and cooler East, so I’m not exactly breaking the mold with this forecast. It looks like we’re all in the same boat with this one. The only thing left to see is if we can sail to victory or go down with the ship in defeat.
As always, the forecast anomalies are based off the latest 30-year normals (1981-2010).