INDIANAPOLIS (WISH) — Indianapolis has had below-average snowfall for nine of the last 10 winters.

Could the 2024-25 season be the one where we turn it around?

There are many factors that contribute to the December to February winter outlook. One of the main clues every year can be found off of the South American coast.

El Niño and La Niña

Sam Lashley is the warning coordination meteorologist with the National Weather Service office in Indianapolis. Part of his job includes coordinating news from the office to the outside world.

He says the El Niño central Indiana experienced in 2023 was caused by waters in the Pacific Ocean near the equator being warmer than normal.

“That (warmth) affects the wind in the atmosphere, and that affects the jet stream which affects our weather,” Lashley said. “This winter, we are looking at a weak La Niña, and that’s where the ocean waters are cooler than normal.”

Those cooler-than-normal water temperatures in the Pacific Ocean have an impact on our average jet stream pattern during winter.

A subtropical jet stream further north and the polar jet stream further south in the La Niña phase. That tends to favor above-average precipitation for the Ohio River Valley.

Similar La Niña winters in Indianapolis

Sometimes you have to look at the past to predict the future.

Over the 15 previous weak La Niña winters, since 1950, Indianapolis has averaged above-average precipitation, slightly below-average snowfall.

In weak La Niña winters, more outside factors can impact the forecast. Small-scale jet stream shifts leading up to any event could have a profound impact on getting rain, snow, or a wintry mix.

Dealing with different types of precipitation this winter also may be a challenge because of the more active storm track.

2024-25 winter outlook

National Oceanic and Atmospheric Administration’s updated winter outlook for the 2024-25 season is favoring above-average precipitation in Indiana. However, this pattern doesn’t necessarily guarantee above-average snow.

Lashley says, “People hear above-normal precipitation and immediately think above-normal snowfall. But, as we have mentioned we have seen several winters of La Niña over the past 10 years and haven’t had above-normal snowfall yet with them. So, it’s the timing with that precipitation and where the jet stream is at.”

For last year’s El Niño winter, Indy picked up a measly 8.2 inches from December to February. In comparison to that number, this winter will be different.

“We’re pretty confident we are going to have snowfall amounts greater than last year that’s the one thing. But overall, the last decade we have struggled to even get to 20 inches. Is that a short-term pattern? Is that more representative for the pattern in the area? It’s still a little bit unsure.”

There is a small signal temperatures will be just above average as a whole through winter in Indiana from NOAA’s outlook. The winter outlook is an average for multiple months, we could still have a week or two of much cooler air and still finish milder than average.

Remember this winter that the wording of wind chill watches/advisories/warnings do not exist.

Extreme cold watches, warnings, and cold weather advisories are the new terms used to emphasize that “cold is cold no matter the wind speed.”

No winter outlook is perfect, but they can be great for giving the overall broad picture of what to anticipate.

Find the latest short-term forecast from the Storm Track 8 weather blog.