PENNSYLVANIA (WHTM) — The National Oceanic and Atmospheric Administration (NOAA) predicts this winter is likely to occur with La Niña conditions, which meteorologist Dan Tomaso said will likely lead to wetter conditions west of Pennsylvania, drier conditions south of Pennsylvania, but a bit of a mixed message for the Keystone State itself.
La Niña and El Niño weather patterns are dictated by conditions in the tropical Pacific near the equator, Tomaso explained. When that part of the ocean is cooler than average due to stronger winds, La Niña conditions emerge.
“That may seem like, ‘Well, what’s the big deal? You have periods of warm and cold, and they go back and forth,'” Tomaso said. “Well, we know from research and statistics that those changes have big impacts on the overall weather pattern…so even though we’re talking about the Pacific, the impacts go all the way across the United States to the Atlantic Ocean.”
El Niño winter weather is a bit easier to predict than La Niña winter weather in Pennsylvania, Tomaso noted (El Niño usually means noreasters and big storms). But looking at previous La Niña winters in the state can offer some insight for those who like to plan ahead.
Last winter in Pennsylvania — which was also a La Niña winter — saw slightly above-average snowfall and near-average to above-average temperatures, Tomaso said, so Pennsylvanians may be able to expect similar conditions this winter.
NOAA maps predict slightly greater-than-average precipitation for the western approximately two-thirds of the state, while the eastern third has equal chances of above- or below-average precipitation.
An overall trend of warming related to climate change decreases the chances of extended cold spells, Tomaso said, which could impact the type of precipitation Pennsylvanians experience this winter.