El Niño forecast points to top-tier strength by fall
U.S. forecasters say the Pacific warming pattern could rank among the strongest recorded, raising risks for extreme weather into winter.
By Sofia Marchetti · World Affairs Correspondent
3 min read
U.S. forecasters said Thursday that the developing El Niño has an 81% chance of reaching the strongest category by fall. The outlook matters because El Niño can shift weather patterns worldwide, raising the odds of drought, heavy rain and heat waves in the months ahead.
The National Oceanic and Atmospheric Administration said in its monthly update that this year’s event could become “very strong,” the agency’s highest classification. NOAA said it is likely to rank among the most intense El Niños since the agency began tracking them in 1950.
El Niño is the periodic warming of waters in the equatorial Pacific Ocean. That warming can affect storms, rainfall and temperatures far from the Pacific, with the largest effects from this event expected in fall and winter, according to meteorologists cited by The Associated Press.
The pattern formed last month and has already moved past the weak stage, NOAA said. It is now considered moderate, and the agency said there are no signs yet that its strengthening is easing.
Scientists told The Associated Press that ocean temperatures in key Pacific regions used to measure El Niño are at or near records for this point in the year. Meteorologists said human-caused climate change, driven by the burning of coal, oil and natural gas, is adding to the ocean warmth on which this El Niño is building.
Emily Becker, a University of Miami scientist who works with NOAA’s El Niño forecast team, told The Associated Press the event is unusual, though not without precedent. Becker said it could compare with the 1997-98 El Niño.
The World Bank has said the El Niño that began in 1997 was linked to weather disasters that killed 23,000 people, pushed poverty rates higher in some countries and cost governments as much as $45 billion.
Daniel Swain, a climate scientist with University of California Agriculture and Natural Resources, told The Associated Press that this event is already setting records for the time of year. He said its effects may differ from past powerful El Niños because it is occurring against a warmer climate baseline.
A very strong ocean signal does not guarantee more severe extreme weather, Becker said. It does, however, increase the chances that certain weather patterns will occur.
For the United States, Becker said El Niño raises the likelihood of a wetter winter across much of the South. It also increases the odds of warmer winter conditions in the northern United States and Canada.
El Niño often suppresses Atlantic hurricane activity. Colorado State University, whose researchers issue widely followed seasonal hurricane forecasts, cut its storm outlook Wednesday because of growing confidence in a strong or very strong El Niño and projected Atlantic activity to be well below normal.
Outside North America, Becker said the pattern makes drier conditions in Indonesia and warmer, wetter conditions in the eastern Pacific more likely.
Swain wrote in a blog post that El Niño releases heat stored below the surface of the tropical Pacific into the atmosphere, warming the planet for a period before that heat dissipates. Zack Labe, a climate scientist at Climate Central, told The Associated Press that a strong El Niño would increase the odds of new climate records during the next six to 12 months.
This story draws on original reporting from Fortune.