El Nino takes hold; Odds favor another mild winter

+1.5C Current Pacific SST’s off Central & South American coasts

81% Chance of El Nino conditions by October-December

60% to 80% Historical chance of warmer than average temps next winter in Minnesota & the Upper Midwest in El Nino winters

“A butterfly can flutter its wings over a flower in China and cause a hurricane in the Caribbean. They can even calculate the odds. It just isn’t likely. And it takes…so long.”

-Robert Redford as math wise card shark Jack Weil in Havana

The “innumerable” interconnections of nature mean a butterfly’s flap could cause a tornado – or, for all we know, could prevent one. Similarly, should we make even a tiny alteration to nature, “we shall never know what would have happened if we had not disturbed it.”

-Peter Dizikes musing on the meaning MIT meteorologist Edward Lorenz’ “Butterfly Effect”

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Edward Lorenz’ “Butterfly Effect”

Source: Wikipedia

Weather & Climate as Chaos Theory?

In the Sydney Pollack movie Havana, Robert Redford pines over his lost love (Lena Olin) by referring to the Butterfly Effect.

The idea is, tiny changes in atmospheric conditions in one part of the world can have immense consequences somewhere else.

This may not be exactly what MIT meteorologist Edward Lorenz meant when he opened the door to what is now called “chaos theory” but it does make you realize the meteorological world is more “connected” than we once thought.

A revolution in seasonal forecasting:

If you really think about it, meteorologists and climatologists have made incredible strides in predictability in both short term forecasts (weather) and longer term seasonal outlooks (climate) in the past few decades.

When I started this career in the 1980s, El Nino was almost an unknown phenomenon. When the massive 1987 El Nino began to pound California with massive storms, climate experts and meteorologists began to realize there was something going on the tropical Pacific Ocean that had impacts thousands of miles away.

The discovery of the “linkage” between El Nino/La Nina phases and regional seasonal trends in weather patterns has been an increasingly valuable tool in seasonal forecasting.

El Nino Returns:

The tropical Pacific heated up in June & July. Take a look at the latest images from a nice piece put together by meteorologist Mike Baker from the Denver-Boulder NWS.

(Click on imgaes for a bigger view)

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Images from Mike Baker-Denver-Boulder NWS

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The best science at this point leaves little doubt that a moderate to strong El Nino event is likely this winter.

Another Mild Winter Ahead?

Statistics show a strong bias toward milder than average winters in Minnesota and the Upper Midwest during El Nino years. It’s not a slam dunk, but the historical odds favor milder than average winters to the tune of about 60% to 80% in El Nino years.

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Source: NOAA/CPC

If you overlay the background hum of a warming climate on top of El Nino, I’m tempted to say there is an even higher chance (maybe 90%?) of a milder than average winter for Minnesota in 2012-’13. But nothing in weather & seasonal forecasting is certain.

As for snowfall, it stands to reason that a milder winter will produce less than average snowfall…but it’s also not a certainty. Still, historical data from NOAA’s CPC does support less snowfall for Minnesota in El Nino winters.

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Source: NOAA/CPC

Indeed the latest seasonal outlooks from CPC place the best odds for a warm winter right over the Upper Midwest and Great Lakes.

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Source: NOAA/CPC

Other effects from El Nino tend to favor wetter than average winters from Southern California through the Desert Southwest and southern states.

Time will tell, but it looks right now like we may see another mild winter with below average snowfall for Minnesota.

In the meantime, carry on with summer and fall!


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