NOAA Forecasts Warm, Wet Winter Driven By El Niño

A powerful El Niño pattern forming in the tropical Pacific is reshaping winter weather expectations across the United States, with federal forecasters projecting above-average temperatures for much of the country and increased precipitation in several regions.

The National Oceanic and Atmospheric Administration released its seasonal outlook this week, predicting warmer and wetter conditions for the season ahead. Ken Graham, director of NOAA's National Weather Service, described the phenomenon driving the forecast as a strong El Niño, if not a historic one. Meteorologists and climate scientists have pointed to record-warm waters off the West Coast contributing to current storm activity, with NASA climate scientist Josh Willis comparing the pattern's behavior to Godzilla. Forecasters cautioned that seasonal outlooks describe odds rather than certainties, noting that El Niño tilts conditions without guaranteeing specific outcomes.

El Niño is a recurring natural climate pattern that originates in the tropical Pacific Ocean, where equatorial waters warm every few years, releasing heat into the atmosphere. This cycle begins with a Kelvin wave, a band of warm water that raises sea levels. Dillon Amaya of North Carolina State University said a wave reached the coast in early October and contributed to coastal flooding associated with Tropical Storm Rachel. Another wave moved off California between Los Angeles and San Francisco in late October, with additional waves expected through early winter.

Regional forecasts vary significantly. Northern California is expected to see warmer temperatures, while the state as a whole, particularly the south, may receive above-average precipitation. Parts of Nevada, the southern Rockies, and California's San Bernardino Mountains could record higher snowfall. The Pacific Northwest is forecast to be warmer, though some areas may receive less precipitation than normal, potentially reducing snowpack. NOAA meteorologist Jon Gottschalck said he expects drought conditions in western Oregon and Western Washington to improve and possibly end.

The Northeast and Mid-Atlantic regions are expected to see warmer and wetter conditions, with flooding potential comparable to a record-setting 2023 El Niño event. Research indicates that El Niño can increase the frequency of nor'easters by pushing warm, moist air northward. Snow remains possible: a strong El Niño in 2016 produced a blizzard that dropped more than 30 inches of snow with 60 mph gusts. Graham said the pattern does not erase that risk.

The South carries the highest probability of above-average precipitation. Gottschalck said snow could reach areas that rarely see it, including northern Texas. Northern Florida, southern Georgia, and South Carolina have the highest odds in the continental United States for a wetter winter. Florida's tornado risk typically rises during El Niño years; a 1998 outbreak in Central Florida killed 42 people.

In the Midwest, particularly the Upper Midwest, warmer temperatures are expected to produce a smaller snowpack than normal. Michigan, Ohio, and Indiana tend to be drier during El Niño winters, while Iowa tends to be wetter, according to the U.S. Geological Survey. Gottschalck said drought is expected to persist across the region this winter, with concern growing that it could worsen.

Climate scientist Daniel Swain said El Niño is partly responsible for recent severe flooding in the Four Corners region in late October, which forced rooftop rescues and evacuations after two months of unusually wet weather. He added that the marine heat wave driving moisture into storms can largely be attributed to human-caused climate change, and that the rain will not end the Colorado River basin's water crisis. Lake Powell and Lake Mead remain at record lows.