Behind the Forecast: How cooler Pacific Ocean temperatures impact Kentucky, Indiana

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Science Behind the Forecast: La Niña and our weather

LOUISVILLE, Ky. (WAVE) - La Niña is the lesser-known sibling of El Niño, but it can still have a significant impact on the weather across the globe. 

La Niña the periodic cooling of the central and eastern Pacific Ocean near the equator.

 The National Oceanic and Atmospheric Association’s (NOAA) Climate Prediction Center (CPC), along with the International Research Institute for Climate and Society (IRI), issued a La Niña watch last week. They distribute an Outlook on the El Niño-Southern Oscillation (ENSO) on the second Thursday of each month. La Nino is part of ENSO. 

A La Niña Watch is issued when conditions are favorable for its development within six months. NOAA’s scientists believe that there is a 50% to 55% of La Niña conditions developing during the Fall and lasting through Winter. There is a 40 to 45% chance of neither a La Niña or El Niño, which is called the neutral phase. There’s also a 5 to 10% chance for an El Niño. 

"The forecaster consensus slightly favors La Niña development during the August-October season, and then lasting through the remainder of 2020," explained National Oceanic and Atmospheric Association's Outlook.

The following are criteria for a La Niña, according to the Climate Prediction Center.

So far, the water over the central and eastern Pacific Ocean near the equator is not cool enough to meet NOAA's criteria. 

So how is La Niña important in our area? 

A strong La Niña has a better chance of affecting Kentucky and Indiana weather compared to weaker events. More significant impacts are seen in our area during the mid-Winter through Spring. 

It’s important to note that La Niña’s impact on the Ohio Valley is small. La Niña’s are different each time, so the same impacts may not be seen. This year’s potential La Niña is expected to be weak, and the strength of La Niña plays a big role in its impact here. 

La Niña is just one piece of the puzzle that controls our weather, so everything must be taken into account. 

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