The Washington Post

Mild February in Washington area might well give way to colder March


After an exceptiona­lly warm January and February, one might expect to leap ahead into spring during March. But not this time: The evolving weather patterns are conspiring to deliver a parting shot from winter.

We project normal to below normal March temperatur­es — averaging 45 to 48 degrees, compared with the norm of 47.6 degrees. March could well be colder than February for the first time since 2018 and 2017. Precipitat­ion should be near to above normal with 3.25 to 4.5 inches of rain and melted snow (the norm is 3.5 inches). Between 0.5 and 4 inches of snow is a reasonable expectatio­n (the March norm is 2 inches), which is more than we’ve seen the entire winter so far.

While March is starting on the mild side this week, we are monitoring changes in the Pacific Ocean and the Arctic that should help a colder pattern become establishe­d during the month’s second week. Also, the La Niña event — which tends to limit precipitat­ion — is weakening, which should increase rain and snow chances into spring after a relatively dry January and February.

We need only to look back to the winters of 2017 and 2018 for examples of how March could play out. Those were also La Niña winters, which featured a mild February before a chilly March featuring some snow. Both of those winters saw more snow in March than any other winter month. Two inches fell in 2017, and 4.5 inches fell in 2018.

With the colder pattern returning, forecast models are indeed projecting snowfall, particular­ly in the March 10 to 20 window. It’s impossible to predict snowfall timing and amounts more than several days into the future, and the models could be wrong, but they show the potential for some accumulati­on given a pattern that is cooler than normal and stormy.

How March could evolve

The models generally project a mild first week of the month before a colder shift during the second week. As such, the first half of March should have close to normal temperatur­es. Precipitat­ion simulation­s suggest near to above average amounts during this time frame.

Projection­s for the second half of the month vary more among the models, lowering our confidence in the outlook. However, two out of the three reliable long-range models project colder and wetter than average weather.

The European and American GFS models suggest that the cool and wet pattern expected to develop mid-month will persist through the end. However, the American CFS model expects the pattern to revert to the regime seen during January and February — with milder, drier weather.

We lean toward the cooler outcome, meaning we should have some speed bumps on the way into spring.

 ?? Joe Flood/flickr ?? A bloom in February, which saw warmer weather than usual. However, winter could deliver a parting shot this month.
Joe Flood/flickr A bloom in February, which saw warmer weather than usual. However, winter could deliver a parting shot this month.

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