NASHVILLE, Tenn. (WKRN) — When it comes to Tennessee weather, it seems like it can be sunny one minute and the next its raining.

The weather patterns are often influenced by larger, climatologically based patterns. There’s one particular pattern that’s a common talking point as we head into winter, and that is El Niño and La Niña.

But what do those terms mean, and why are they important to this area?

Let’s start with El Niño. This phenomenon references the impact of the Trade Winds on the Equatorial Pacific Ocean. The Trade Winds, which blow East to West, help to keep warmer water toward the Central Pacific. However, there are periods of time when the Trade Winds weaken, or nearly halt, allowing warmer water to drift eastward to the North American/South American coastline. That phenomenon is called El Niño, and it often results in a relatively dry winter for our region.

On the flip side, La Niña occurs when the Trade Winds strengthen, and the water in the Eastern Equatorial Pacific (along the North and South American coasts) becomes cooler than average. La Niña typically results in a wet winter pattern for Middle Tennessee.

According to the Climate Prediction Center, La Niña conditions are developing, and there’s an 87% chance it continues December 2021 through February 2022.

Before we get to winter, however, we are entering a secondary severe weather season. Make sure you have a severe weather preparedness plan!

Behind the cold front, we turn cooler and less humid. Beautiful conditions move in for Friday & Saturday.