Along with issuing the Winter Outlook and November forecast last week, the Climate Prediction Center recently updated the 90 day outlook. It covers November, December and January and has a lot of similarities with the previous mentioned forecasts: warmer than normal temperatures over much of the nation, and drier than average weather across the southern tier of the nation.
A small area in Washington is highlighted for colder than normal weather. Above average precipitation is forecast for the Pacific Northwest and Northern Plains.
The lack of precipitation expected from the Southeast to the Southwest will aid in the ongoing drought in the Southwest and southern Plains. Some expansion is also anticipated. Drought conditions are expected to improve in the Northwest and New England.
As with the Winter Outlook, the driving force behind the 90 day forecast is an anticipated strong La Niña pattern, meaning the water temperatures in the equatorial pacific ocean are likely to be colder than average. The CPC states that La Nina conditions are starting to be observed in the Pacific Ocean and are expected into early next year. La Nina was discussed earlier this month by the CPC with an La Nina Advisory. The trends of an El Nino or La Nina often take time to establish, so its effects will be seen gradually through the end of 2020. Model forecasts were also used to determine the upcoming influence of La Nina through the period.