Experts predicting a wetter, colder winter

After an abnormally warm and relatively snowless winter last year, meteorologists are anticipating a colder, snowier winter this time around.

Scientists are projecting a 60 percent chance that weather patterns will shift into a “weak La Nina,” which could cause wetter, colder weather in the Great Plains region, including Iowa.

Despite this, State Climatologist Justin Glisan said there isn’t clear guidance for Iowa specifically.

“We are categorized in ‘Equal Chances’ of above/below/near-average [temperatures],” Glisan said in an email. ”There is a slight lean for wetter conditions in Eastern Iowa. In weak La Nina winters, we have generally experienced above-normal seasonal snowfall totals across much of the state.“

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Glisan said there were three consecutive La Nina winters between 2020 and 2022. This was the third time that has happened since 1950.

Rich Kinney, a warning coordination meteorologist with the National Weather Service’s Quad Cities bureau, said the shifted climate pattern will bring colder temperatures to Iowa throughout December, January and February, with about average snowfall.

“We're certainly expecting more frequent snow and more cold periods than last winter,” Kinney said. “We're looking at a more active winter this time around.”

Historically, Kinney said the average December temperature is about 25.5 degrees, January’s average is 19.6, and February’s is 24.1.

Despite typical snowfall being anticipated for Iowa, overall wetter-than-average precipitation is possible in eastern and northeast Iowa, much of Illinois, and the Great Lakes states, according to the National Oceanic and Atmospheric Administration’s winter outlook study.

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What’s a La Nina?

La Nina is a natural weather pattern that occurs when the temperatures of the Pacific Ocean are cooler than normal.

La Nina — also simply called “a cold event” — is often paired with El Niño, which happens when the ocean temperature is warmer than normal.

La Nina conditions occur about every two to seven years, while El Niño conditions are more frequent, according to the NOAA.

Although a La Nina pattern tends to favor cooler and wetter temperatures in the Midwest and northeast regions, the climate pattern can hit southern states with warmer than average temperatures.

During one of these climate shifts, the water in the Pacific Ocean becomes significantly cooler. A “weak” La Nina means the cold temperature of the ocean is less pronounced.

Jon Gottschalk, chief of the Operational Prediction Branch of the Climate Prediction Center and author of the Winter Outlook report, said winter conditions can be difficult to forecast, but this year is particularly difficult due to the La Nina.

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“This year will be very different than last year because of it,” Gottschalk said, referencing La Nina.

He said a weaker La Nina with a shorter duration predicted means this winter will be “quite variable” in some areas.

Gottschalk said Iowa should expect a “cold blast” in the next few weeks.

“We see this kind of lagging month into November,” Gottschalk said about the region’s temperature. “It seems as we get toward December [and] January, we will get more normal winter variability changes.”

Drought mitigation

Drought conditions are expected to continue throughout the Great Plains. But Gottschalck said he anticipates the drought in Iowa to improve.

Kinney, with the Quad Cities bureau, said if Iowa gets near-normal snowfall, it could contribute to improving soil moisture across the state, leading to “somewhat improved drought conditions.”

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But there are many factors, he said, including if Iowa will see snowfall before the ground freezes across the state.

This comes after the U.S. Drought Monitor’s latest report shows some drought subsiding in Iowa, due to significant rain throughout the state. Last week’s report — based on conditions measured on Tuesday, Nov. 5 — showed a 37.9 percent drop in severe drought conditions.

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; olivia.cohen@thegazette.com