El Niño Strengthening: How That Could Affect Snowfall In PA

PENNSYLVANIA — Meteorologists are saying with confidence that the El Niño climate pattern is strengthening and will last through spring, but does that mean we’ll have to shovel massive amounts of snow in Pennsylvania this winter?

The Climate Prediction Center says with 100 percent certainty the strengthening El Niño weather pattern will last through early winter, and with 90 percent certainty that it will last until spring. The agency, a division of the National Oceanic and Atmospheric Administration, expects the El Niño pattern to bring warmer, wetter conditions to parts of Pennsylvania this winter - and more snow than average for certain areas.

In most El Niño winters, Pennsylvania has below-average snowfall from January to March everywhere but the southeast portion of the state, which typically sees a bit more snow than average. In moderate to strong El Niño winters, we normally see much less snowfall in the northern and central parts of the state. Pittsburgh typically sees less snow in these winters, while Philadelphia will typically gain a few inches.

In general, areas like the Four Corners states, the Texas and Oklahoma panhandles, and the southern Appalachia region could see more snow — or rain, depending on the temperatures — this winter, according to the Climate Prediction Center.

But in other parts of North America, “El Niño appears to be the great snowfall suppressor.” Michelle L’Heureux, a meteorologist with the agency, wrote in a post last week.

That’s the likely scenario for the area around the Great Lakes, interior New England, the northern Rockies and the Pacific Northwest, extending far into western Canada and over most of Alaska, L’Heureux wrote.

Oregon, Washington, New York and Pennsylvania are the states most likely to see below-average snowfall during a powerful El Niño.

That said, “El Niño nudges the odds in favor of certain climate outcomes, but never ensures them,” L’Heureux added.

This year’s El Niño, which began developing in June, is the first in four years. Not all El Niños are the same, and that adds uncertainty to winter forecasts, according to The Weather Channel.

In general, the forecast calls for warmer-than-average temperatures in the northern U.S. from the Great Lakes to western Canada to Alaska; drier-than-normal conditions in the Midwest and Ohio Valley; wetter conditions in the Southwest; and cooler-than-normal temperatures in the South and Southeast.

The winter of 2015-16 was the warmest U.S. winter on record, and the El Niño that year was one of the strongest on record. Still, it delivered a massive storm to the Northeast in late January 2016. Just because El Niño winters often mean lower snowfall totals overall, catastrophic storms aren’t out of the question.

By comparison, El Niño barely whimpered in 2009-10, “and just barely nudged into strong territory by winter,” The Weather Channel noted.

El Niño isn’t the only driver in winter weather patterns. Air temperatures and climate change play a big role, too, according to the Climate Prediction Center’s L’Heureux.

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