Tim’s 2015 – 2016 DC Winter Forecast

For Tim’s latest 2016 – 2017 Winter Forecast, please click here

A strong El Nino is brewing in the Pacific Ocean, the waters off of the western coast of the United States remain warm (positive Pacific Decadal Oscillation) and October Siberian snowfall is currently running a bit above normal. How much snow can the Washington Area expect this Winter?

Tim’s Washington DC Region 2015 – 2016 Snowfall Forecast (Click on image for larger view)
Tim’s Washington DC Metropolitan Area 2015 – 2016 Snowfall Forecast (Click on image for larger view)

This is a very tough winter forecast as strong El Nino winters in the past have produced either very wet or very snowy conditions in the Mid-Atlantic.

The key will be the behavior of the Arctic Oscillation (AO) and whether or not it can go into its negative phase which would allow cold air to infiltrate the eastern United States from Canada.

The arguments for above normal snowfall:

Siberian snowfall in October is currently off to a healthy start:   there is a fairly strong correlation with colder temperatures during winter occurring in the eastern United States following above normal Siberian snowfall in October.

While the current Siberian snowfall is not off the charts, it is at least a bit above the seasonal average and that may bode well for some cold shots moving into the eastern United States during the upcoming winter.

Moderate to Strong El Nino Winters with a Positive (warm phase) PDO (Click on image for larger view)
Moderate to Strong El Nino Winters with a Positive (warm phase) PDO (Click on image for larger view)

The Pacific Decadal Oscillation remains in its warm (or positive) phase: Just like last year, warm water is parked along the southern coast of Alaska and continuing southward along the Pacific northwest coast of the United States. This should favor more ridging off of the west coast of  North America and if these warmer waters hold, could allow shots of colder air to infiltrate the eastern half of the nation.

Sea Surface Temperature Analogs
Sea Surface Temperature Analogs

El Nino is forecasted to weaken during the second half of winter:  Winter may very well start off milder than average in December with very little cold air to work with through mid January.  As El Nino begins to weaken during the second half of winter, colder air may begin to infiltrate the eastern half of the nation increasing the prospects of several good snow storms.

El Nino is forecasted to start out strong before weakening through the mid to late winter.

El Nino is forecasted to start out strong before weakening through the mid to late winter.

Let’s take a look at temperature and precipitation trends based on the analogs from previous strong to moderate El Nino winters with a Positive PDO:

Analog package for temperatures: potential for near normal to slightly below normal temperatures for entire winter season

Analog package for temperatures: potential for near normal to slightly below normal temperatures in the Mid-Atlantic
Analog package for precipitation: Potential for above normal precipitation.

Analog package for precipitation: Potential for above normal precipitation in the Mid-Atlantic.

Upcoming Winter Forecast for Midwest, Mid-Atlantic and New England:

Winter_2015_16_Headlines

Average Snowfall in the Washington DC Region:

washington_dc_region_average_snowfall_dcstorms-com

Average Snowfall in the Washington DC Metropolitan Area:

washington_metro_average_seasonal_snowfall_dcstorms-com

 

To recap:

Winter may start out milder than average continuing through January but as El Nino begins to weaken, colder air may become entrenched in the eastern half of the nation from mid/late January through early March.

The forecast is extremely tricky this year because previous strong El Nino winters have produced wild swings in snowfall totals from very little (1997-98) to above average (1957-58, 1982-83, 1986-87).

The behavior of the NAO (North Atlantic Oscillation) and Arctic Oscillation (AO) can’t be predicted more than about 2 weeks out and will dictate whether precipitation falls mainly as rain or snow this winter.

According to the analogs that I chose, temperatures in DC should run near to slightly below average and precipitation should be above average.

22 Replies to “Tim’s 2015 – 2016 DC Winter Forecast”

  1. Hi Tim,
    Thanks for another great report! As a snow / Christmas Season lover I always hope for a combination of the two. Does a white Christmas look less likely this year than normal based on the stronger El Nino ? Am I correct in assuming the more negative the AO short term outlook, the better chance of colder weather ? Thanks again, I have been looking forward to your very accurate forecasts since 2009 – 2010 !

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    1. The Arctic Oscillation is impossible to forecast up until about one to two weeks out at best. When the AO is negative, the polar jet stream weakens letting the bitter cold in Canada travel into the lower 48. So yes, the more negative the AO, the colder the temperatures are in the lower 48. If the AO goes negative and a “juicy” southern tracking storm heads north out of the Gulf of Mexico and up the eastern seaboard (just like in December of 2009) … a White Christmas is not impossible. Its still only mid October… if the Siberian snowfall goes well above normal by early November then that may be promising for more snow versus rain. But this looks like a moist winter… and thats good news after such a dry second half of the year!

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  2. thanks tim, I know you put alot of work and thought into this forecast; it comes across very professional without your personal hopes for alot of snow; i think as the winter unfolds, you have given yourself some wiggle room to explain why things are going as they are.

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  3. Great forecast. So do you think all the precipitation will be rain in December? Also what about 2010 when we had snow mageddon? Was that during a strong El Nino or weak?

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    1. The temperatures and precipitation are taken from analogs so they are simply generalizations. Its possible December could have both some cold and mild periods. If moisture interacts with the cold then we have some snow. 2009 – 2010 was a moderate El Nino. As usual if winter starts out slow… February always has the potential for a blockbuster. We could get a ton of rain in December and January and then a blockbuster nor’easter in February with our entire winter snowfall in one storm.

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  4. How did all those storms form in 2009-10? It kind of sounds like last winser when we had moisture but we got most of the snow in 3 storms. So do you think most of the storms will be coastal?

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    1. 2009-2010 was an El Nino year. El Nino winters feature an active southern branch of the Jet Stream so that storms move across the southern tier of the United States before possibly coming up the Mid-Atlantic coast. We should have ample opportunity for this… will it be rain or snow… ?? Depends on the Arctic Oscillation. When the Arctic Oscillation is in its negative phase, colder air moves south out of Canada. However if the storminess comes up the coast with a positive phase of the AO… we could be looking at heavy rain. Siberian snowfall is a factor to look at because when it is above average in October, a prominent climatologist has noticed a link between that and the AO being more negative.

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  5. This is what I like to see! I don’t completely remember the 2009-2010 season (because I was too young to remember), so I am excited to see what this year brings us! After the 2012-2013 season ended, with little snow in my area from what were expected to be big snowstorms *cough *cough Snowquester *cough *cough, I stopped enjoying the weather. Of course, I completely missed out on the 2013-2014 season, so I got back into the weather. I really hope this is how this season goes. While I’m here, may I ask, if this forecast is wrong, what do you think the minimum snowfall will be for the D.C area? I know it’s a while out, but I would like to know what you think is the least we could get from this winter.

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    1. 1997-98 was a strong El Nino and we wound up with tons of rain and only a tenth of an inch of snow at National Airport. This year is also one of the strongest El Ninos we have seen (since records of El Ninos have been kept — 1960s/1970s). The two keys is that Siberian Snowfall is above normal and the PDO remains in its warm phase both bode well for some cold shots of air mid to late winter. Given that the El Nino is strong… we will have ample shots of moisture-rich storms. All it takes is one massive snow storm to give us our entire winter seasonal snowfall. Nobody could know for sure exactly how little or how high the totals will be here in the Washington Region — but based on the trends… probabilities are running optimistically high.

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  6. Hi Tim, any guess on when we can expect the first snowfall of the year?

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    1. On average, the first inch of snow falls early to mid December.

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  7. So do you think a lot like last year or less snow for southern maryland this year

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  8. Tim,
    I have read your forecast a couple times and other forecasts. There seems to be a difference. Half of them say below average snowfall and the other half say above average snow. I LOVE snow! Which ones are right and which are wrong? I know it will be moist, could Snow-Mageddon occur again? It’s been 6 years since then. Thanks for the forecast.

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  9. I am beginning to think that Northern VA will not have a significant snowstorm between January and March 2016. Is Mother Nature toying with us??

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  10. It seems that during the Holiday season, when we look forward to snow, it seldom materializes. Even during above average winters, the snow season is back end loaded and often does start until January. So frustration this time of year in DC does not prove or disprove that the winter as a whole will be a flop.

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