She’s back! La Ni単a conditions take hold in the Pacific

By Tom Yulsman | November 10, 2016 11:40 am

But will La Ni単a last for long?

Cooler than normal sea surface temperatures indicative of La Ni単a conditions stretch across most of the eastern and central equatorial Pacific. (Source: earth.nullschool.net)

Cooler than normal sea surface temperatures indicative of La Ni単a conditions stretch across most of the eastern and central equatorial Pacific. (Source: earth.nullschool.net)

After much anticipation, La Ni単a is finally here.

During October and now into November, cooler than normal sea surface temperatures indicative of this weather-altering phenomenonhave been stretching across most of the eastern and central equatorial Pacific Ocean.

Here’s a summary of the situation from today’s update by the Climate Prediction Center of the National Weather Service:

. . . the forecaster consensus favors the continuation of weak La Ni単a conditions through December-February (DJF) 2016-17. At this time, the consensus favors La Ni単a to be short-lived, with ENSO-neutral favored beyond DJF.

The forecast pegs the odds of theseconditions persisting through winter of 2016-17at 55 percent.

What might this mean weather-wise for North America?

Typical impacts of La Ni単a on U.S. winter temperature and precipitation. Such impacts have been associated with past episodes, but all impacts aren't seen with every episode. (Source: NOAA Climate.gov drawing by Fiona Martin.)

Typical impacts of La Ni単a on U.S. winter temperature and precipitation. Such impacts have been associated with past episodes, but all impacts aren’t seen with every episode. (Source: NOAA Climate.gov drawing by Fiona Martin.)

La Ni単a typically tilts the odds in favor of below-average precipitation and above-average temperatures in thesouthern tierof the United States. Meanwhile,colder and wetter conditionsare favored across the northern part of the nation, and large swaths of Canada as well.

The Pacific Northwest already has been drenched in copious rainfall in recent weeks, with many records set for soggiest October. But it probably would be simplisticto pin this all on a weakLa Ni単a, since other powerful climatic factors are likelyat play as well.

SEE ALSO:Watch intense rivers of atmospheric moisture spray the Pacific Northwest like a firehose

Just what is La Ni単a? It is the flip side of the coin from El Ni単o the other half of what’s known as the “El Ni単o-Southern Oscillation, or ENSO.

La Ni単a disrupts normal patterns of precipitation and atmospheric circulation in the tropical Pacific. Abnormally cold surface waters developin the eastern and central equatorial Pacific. This tends to suppress cloudiness and rainfall there, especially during the Northern Hemisphere winter and spring. Meanwhile, far to the west, rainfall is enhanced over Indonesia, Malaysia and northern Australia.

CATEGORIZED UNDER: Climate, ENSO, select, Top Posts
MORE ABOUT: climate, ENSO, La Ni単a, weather
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  • RealOldOne2

    Yes, another La Ni単a, natural climate variability continuing just as it always has. And it further falsifies the predictions that the Climate Establishment made in the late 1990s:

    “It appears that we have a very good case for suggesting that El Ni単os are going to become more frequent, and they are going to become more intense, and in a few years or a decade or so, we’ll go into permanent El Ni単o … and you’ll have El Ni単os that last 18 months, 18 years.” – Dr. Russell Snell, 1997

    In the nearly two decades since Snell made that prediction, we’ve had two very strong El Ni単os, two moderate El Ni単os, two weak El Ni単os, one strong La Ni単a, three moderate La Ni単as and five weak La Ni単as, and we are presently in another weak La Ni単a condition. http://ggweather.com/enso/oni.png

    We have added 600 billion tons of CO2 to the atmosphere since Snell made his prediction. That is 40% of all the human CO2 ever produced, yet Snell’s prediction has totally failed as we have had more La Ni単as than El Ni単os.

    And since Snell’s 1997 prediction, the only reason for the small positive temperature trend of the atmosphere has been the very strong natural 2016 El Ni単o. Without that El Ni単o, the temperature of the atmosphere had been flat for over 18 years. https://uploads.disquscdn.com/images/3212c4932d2aa4e5b44cbcda18fbf59ee807a87e740e105dcfd4abbb4b1c9e27.png

    The empirical evidence shows that climate change continues to be caused primarily by natural climate variability, not human CO2.

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ImaGeo

ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.

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