La Niña Impacts on Miami Valley Winter ‘20-’21

Wetter and Warmer Winter Possible

NOAA released a statement on Thursday, September 10, 2020, declaring a weak La Niña pattern has developed and “is likely to persist through winter".

La Niña is an atmospheric phenomenon that is caused by the upwelling of ocean waters creating cooler than normal sea surface temperatures across the central and eastern Pacific Ocean near the equator. The opposite of this is an El Niño, which features warmer than normal sea surface temperatures.

“La Nina can contribute to an increase in Atlantic hurricane activity by weakening the wind shear over the Caribbean Sea and tropical Atlantic Basin, which enables storms to develop and intensify,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “The potential for La Nina development was factored into our updated Atlantic hurricane season outlook issued in August.”

While the initial impact of La Niña will be on the end of the Atlantic Topical Season, there will be secondary impacts on this upcoming winter.

During La Niña winters, the Polar Jet Stream becomes ridged across the Pacific Northwest, creating a trough through the north-central United States.

Particularly across the Miami Valley, a wetter a than normal winter, but whether it’s snow or rain is often decided by other global patterns like the Arctic Oscillation.

According to the National Weather Service in Wilmington, Ohio, the last weak La Niña the Miami Valley experienced was the winter of 2016-2017.

“Precipitation was normal, but temperatures were above normal and snow was 10-15 inches below normal,” says the National Weather Service.