It’s been the talk of the coffee shop – scientists have been forecasting the development of El Niño for months and issued the first El Niño Watch on April 13. In the National Oceanic and Atmospheric Administration’s monthly outlook released on Thursday, forecasters issued an El Niño Advisory, meaning El Niño conditions are now present and expected to gradually strengthen into the winter.
What is El Niño?
El Niño is associated with a band of warm ocean water that develops near the equator in the central and eastern Pacific Ocean, but the impacts on the climate extend far beyond. The natural climate phenomenon occurs on average every two to seven years.
“Depending on its strength, El Niño can cause a range of impacts, such as increasing the risk of heavy rainfall and droughts in certain locations around the world,” says Michelle L’Heureux, climate scientist at the Climate Prediction Center. “Climate change can exacerbate or mitigate certain impacts related to El Niño . For example, El Niño could lead to new records for temperatures, particularly in areas that already experience above-average temperatures during El Niño.”
El Niño’s influence on the U.S. is expected to be weak during the summer months and then become more pronounced in late fall through spring. By winter, there is an 84% chance of greater than a moderate strength El Niño, and a 56% chance of a strong El Niño developing.
Typically, moderate to strong El Niño conditions during the fall and winter result in wetter-than-average conditions from southern California up the Gulf Coast and drier-than-average conditions in the Pacific Northwest and Ohio Valley. El Niño winters also bring better chances for warmer-than-average temperatures across the northern tier of the country.
While most headlines highlight how El Niño can bring historic heat around the globe, agricultural meteorologist Eric Snodgrass says it also tends to bring favorable growing conditions for crops in the Midwest.
Since 1970, Snodgrass says there have been 17 El Niño summers and 14 of them had yields slightly above trendline.
“This means we generally think of El Niño summers having a more juicy atmosphere, or more stuff for thunderstorms,” says Snodgrass, principal atmospheric scientist with Nutrien Ag Solutions.
While El Niño will likely lead to additional wet weather across the southern tier of the country, including the Southern Great Plains, Brad Rippey, U.S. analyst and drought monitor author for USDA, says the recent rain in Texas can’t necessarily be linked to El Niño-related rainfall.
El Niño isn’t to blame for the current drought problems across the U.S. either, he adds. An extremely stubborn atmospheric block of high pressure is situated across northern Canada, which is effectively keeping cold fronts from reaching the Midwest or the Northeast.
“It keeps tropical moisture from working its way up from the South, and it serves as almost a complete block on rainfall reaching some of the nation’s key agricultural areas,” he describes. “Until that block breaks down, we will not see appreciable rain.”
