El Niño is probably coming back this winter. Here's what it means for Indiana weather.

IndyStar

Here's how El Nino typically impacts U.S. winter weather. However, not all impacts occur during every event, and their strength and exact location can vary.

The weather in Indiana leading up to the official start of winter has see-sawed between traffic-snarling ice storms and brief bursts of warmth that have Hoosiers reaching for their jogging shoes.

If you're a fan of the latter, the news that El Niño is probably going to happen this winter will get you one step closer to the slightly warmer winter wonderland you're after.

Federal scientists announced Thursday that there is a 90 percent chance that El Niño will form this winter, and a 60 percent chance that the El Niño will continue into the spring.

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El Niño occurs when sea surface temperatures in the equatorial Pacific ocean are unusually warm. The warm water interacts with the atmosphere and results in a change in weather patterns around the world.

For Indiana, temperatures typically are above average and precipitation is below average, and maps from the Climate Prediction Center suggest that the state will have a drier, warmer winter than usual.

The impact of the weather pattern will be especially noticeable locally considering that the past two winters saw the formation of La Niña, a natural climate pattern that hits Indiana with cooler, wetter winters.

However, experts warn that not every El Niño produces the same effects.

"The arrival of El Niño or La Niña in the tropical Pacific Ocean triggers a cascade of changes in tropical rainfall and wind patterns that echo around the globe," according to the National Oceanic and Atmospheric Administration. "For the United States, the most significant impact is a shift in the path of the mid-latitude jet streams. These swift, high-level winds play a major role in separating warm and cool air masses and steering storms from the Pacific across the U.S.

"Every event is somewhat different. In other words, the influence of El Niño on U.S. winter climate is a matter of probability, not certainty."

The National Weather Service in Indianapolis also reminds Hoosiers that an El Niño doesn’t mean it won’t snow, but to expect less precipitation throughout the winter months.

Mike Halpert, deputy director of NOAA's Climate Prediction Center said that "if an El Niño develops it is expected to be weak. Still, it may influence the winter season by bringing wetter and stormier conditions across the southern United States and drier conditions in parts of the north."

The most recent El Niño occurred during the winter of 2015-16. That was a particularly powerful episode which led to droughts, flooding and coral bleaching in different parts of the world, the World Meteorological Organization said.

The forecast released Thursday said the government's ENSO alert system remains as an "El Niño Watch." Once El Niño develops, the alert level will rise to "El Niño Advisory."

USA Today contributed to this story. Call IndyStar reporter Justin L. Mack at 317-444-6138. Follow him on Twitter: @justinlmack