Measurements indicate that a slowly developing La Niña will affect winter conditions in most of the country. There’s a 60% chance of it emerging somewhere between September to November, with the expectation that it will continue through March, according to the National Weather Service’s Climate Prediction Center.

The main reason for the likely colder and wetter winter is a La Niña weather pattern developing in the Pacific Ocean.

There's been a lot of talk about how a La Niña is likely this winter, but what exactly is that and how could impact the Chicago area?

For the Chicago area, the outlook shows the potential for a wetter-than-normal winter with average temperatures expected.

La Niña refers to the colder ocean waters off the coast of Peru that spark different weather activity for regions around the globe through the jet stream. Typically, La Niña brings colder temperatures and more precipitation to winters in the northern U.S. while the southern states see warmer and drier forecasts.

In its forecast for “meteorological winter,” the National Oceanic and Atmospheric Administration said that La Niña will make December, January and February colder and wetter than normal in several parts of the U.