After nearly four months of waiting for El Niño, the switch is likely to be flipped on this winter. Rejoice, my fellow Ninoheads.
There are signs that El Niño, a climate phenomenon characterized by a warming of waters in the eastern tropical Pacific, is “imminent” according to an update released on Thursday by the International Research Institute for Climate and Society (IRI). It will arrive just in time for winter to rearrange the world’s weather, including ushering in a warmer-than-normal winter for much of the U.S.
The latest update on El Niño that included input from human researchers at IRI and the National Oceanic and Atmospheric Administration (NOAA) was released on Oct. 11. It gave strong odds that El Niño would form in the next month or so. The update released on Thursday uses models only, and finds the odds to be even higher. It puts the chances we’ll see an El Niño from winter until early spring of 2019 at an 85-90 percent.
The conditions in and above the Pacific seem to agree. NOAA defines El Niño as when ocean temperatures in a region of the eastern tropical Pacific (dubbed NINO3.4 in climate nerd talk) are 0.5 degrees Celsius (0.9 degrees Fahrenheit) above normal for three months in a row. That region is currently just over that threshold, and a big pulse of warm water below the surface that’s working its way across the Pacific should help El Niño conditions blossom. It’s not likely to be a blockbuster El Niño, but it should still have enough of an impact as it propagates through the atmosphere to affect weather patterns elsewhere.
And as it so happens, the El Niño update on Thursday coincided with NOAA’s winter weather outlook. Meteorologists know how El Niño can tip the odds one way or the other for certain types of weather, so the outlook is pretty confident in showing higher odds of warmth across much of the U.S. save the Southeast. The outlook also shows wet weather for the southern tier of the country, while the Northern Rockies are likely to be drier than normal. The wet weather in the Southwest would certainly be a relief, since the region is in the grips of an intense drought.
El Niño is far from the only natural climate shift to affect weather. You’ve got your Arctic Oscillation and your Madden-Julian Oscillation (to say nothing of the unnatural shift driven by human-caused climate change). And a forecast for, say, increased odds of a warmer-than-normal winter in Spokane does not mean there will be no cold spells. Sometimes winter just has to winter.