Winter Outlook – Cold and Snowy In Spots

This just-released outlook for the winter months of December-January-February calls for a cold and occasionally snowy late winter for sizeable parts of the Northern Plains, Midwest, and Great Lakes regions. 

December Temperature Outlook

Blue = Colder Than Normal   Brown = Warmer Than Normal

December - January - February Temperature Outlook

December - January - February Precipitation Outlook

Green = Wetter Than Normal   Brown = Drier Than Normal

December - January - February Precipitation Outlook

Science Behind the Outlook

Let’s discuss a number of weather features that could influence the 1- and 3-month outlooks. These include:

Climatology and an Increasingly Active Jet Stream

In the map at right, areas shaded in blue and green receive a relatively-higher amount of precipitation in December while areas shaded in red receive less.

From a climatological perspective, precipitation is enhanced across the Pacific Northwest (PNW) as well as parts of the Southeast. Much lesser amounts of precipitation tend to fall over the Plains.

Secondary Severe Weather Season

Often, winter does not settle in until late December. A battle between mild and colder air can occur early in December with a secondary severe weather season over parts of the South. 

No More El Niño

ENSO Neutral conditions are expected to persist well into 2020. The past weak El Niño (Region Niño 3.4) has ended and should not have any significant impact on winter weather.

Unusually Warm North Pacific Water Persists

However, a persistent area of unusually-warm water over the North Pacific is likely to influence the position of the jet stream, and thereby temperature and precipitation anomalies. 
It’s possible that this “wavy” jet stream pattern could emerge from time to time resulting in unusually-mild coastal temperatures and an unusually-cold middle U.S.

Trends

Despite the recent extremely-cold late Fall, a study of past winter temperature data shows that winter is warming over the entire U.S.