Winter 2022-2023 will feature La Nina conditions (cooler than average water temperatures) across the Equatorial Pacific for the third time in a row, also referred to as a “triple dip La Nina”. A triple dip La Nina has only happened three times since records have been kept: 1954-57, 1973-76 and 1998-2001. So what does this mean for the upcoming winter across the Washington Area?
Will this winter be similar to last year? Not necessarily. La Nina is a bit stronger this year and is also forecast to weaken and or dissipate into neutral conditions as we head into March 2023.
Also unlike last winter, the waters over the northern Pacific ocean are warmer than average also known as the “warm blob” or positive Pacific Decadal Oscillation. A positive PDO favors high pressure building over the western United States from time to time allowing for shots of arctic air to push into the eastern United States.
A winter forecast is about trends, and the devil is always in the details. Taking a look at historic analog years (with similar sea surface temperature anomalies) showed some interesting trends.
For one, December was colder than average across the Mid-Atlantic which may be good news for an early start to winter this year unlike some of the snow-less Decembers of the past.
Snowfall varied at Washington National Airport during each of the twelve analog years:
46″ of snow fell at National Airport during the winter of 1995-96 with the infamous Blizzard of January 1996 paralyzing the region with 2 to 3 feet of snow.
Four years later, on 25 January 2000 a Nor’easter slammed the eastern suburbs of DC with over two feet of snow falling in Prince Georges county while Leesburg received only 8″ from that storm.
I also remember well the winter of 2005-2006 when a pretty intense storm dropped well over a foot of snow in February of 2006 (15-18″ in DC’s western suburbs).
So there you have it, making a winter forecasts is truthfully a long shot and at best only trends in temperatures and precipitation can be predicted.
The below image is my best guess at what could fall across the DC, Baltimore and Philly regions from December 2022 through March 2023.