When will it really snow in Washington?

If you’re thinking it has been a long time since we’ve had a real snowstorm in the Washington area, you’re right. In fact, we’ve gone more than two years without a snowfall of two or more inches.

You have to go all the way back to January 26, 2011, for the last serious snow. Around five to eight inches of the white stuff blanketed the region that afternoon and evening. The storm caused huge traffic jams when people were trying to commute home from work and school.

Since then, it has been slim pickings for snow lovers.

After just two inches of snow in Washington all of last winter, only 1.5 inches had fallen this winter as of Monday. An average winter brings almost eight inches of snow through January and about 15 inches overall. Even the colder and usually snowier spots north and west of the city have had very little snow.

What’s going on?

Last winter La Nina was to blame. La Nina means “little girl” in Spanish. It also refers to times when the waters in the eastern Pacific Ocean along the equator are much cooler than average. When there is a La Nina, Washington winters tend to be warmer and less snowy. Last winter, a strong La Nina led to one of our warmest and least snowy winters on record. Only two winters were warmer and had less snow in the Washington area.

Before the current winter, there were signs that an El Nino would form. El Nino means “little boy” in Spanish. It is the opposite of La Nina and refers to waters in the eastern Pacific Ocean along the equator that are much warmer than average. El Nino can increase the odds of snow here.

But El Nino never showed up. When there is no El Nino or La Nina, it’s harder to predict what kind of winter Washington will have. The pattern so far has mostly kept the region on the warmer, rainier side of storms passing by to our west and north. When it has been cold enough for snow, the storms have missed us or been very weak.

The little snow (and ice) that has fallen has been enough for some schools to close, delay or close early, but barely enough for you to make a snow angel, let alone a snowman!

Any hope for snow lovers?

February is typically Washington’s snowiest month, and we can still get snow in March. So hope is not lost if you like snow. That said, the pattern does not look like an especially snowy one.

One factor meteorologists (weather scientists) look at when predicting snow is called the North Atlantic Oscillation, or NAO. The NAO can be negative, positive or neutral depending on pressure patterns over the northern Atlantic Ocean. A negative NAO often causes the jet stream over the eastern United States to dip south. This can lead to cold and snowy weather for Washington.

The NAO is in its positive, less snowy phase. It’s moving toward neutral, but it’s unclear whether it will become negative (more snowy) anytime soon.

The good news if you like snow? All it takes is one big storm to turn Washington into a winter wonderland.

— Dan Stillman

Stillman is a meteorologist for The Washington Post’s Capital Weather Gang. Get the latest weather forecast and news at washingtonpost.com/capitalweathergang.

 
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