This winter is likely to bring stormy and rainy weather to Florida and the Gulf Coast, below-normal snowfall in the Plains and Great Lakes, drought relief in the Mississippi River valley and the chance of big snowstorms along the Eastern Seaboard, National Oceanic and Atmospheric Administration forecasters said Thursday.
The predictions are based on the presence of two major weather drivers heading into the winter: A strengthening El Niño climate pattern and remarkable warmth lingering in the world’s oceans. Those conditions strongly affect how weather systems and patterns develop, and where.
“Other outcomes are always possible, just less likely,” said Jon Gottschalck, chief of the Climate Prediction Center’s operations prediction branch.
Gottschalck called El Niño “the predominant climate factor driving the U.S. winter outlook this year,” but added that its impact has become increasingly unpredictable in recent decades. At times, other, shorter-term weather drivers have counteracted El Niño’s typical impact.
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El Niño is linked to above-normal waters in the Pacific Ocean, which change global weather patterns in ways that can trigger floods, heat waves, droughts and fires in various regions of the planet.
“No two El Niños are alike, and the impacts of those El Niños are not alike,” said Sarah Kapnick, NOAA’s chief scientist.
Here is what is likely in store for different parts of the United States:
Warmth — and rain? — for the West Coast
El Niño tends to send Pacific moisture streaming across the southern tier of the United States, which has produced major floods and mudslides in Southern California in the past. This winter, that signal is not yet clear, scientists said.
“The uncertainty is very high,” Gottschalck said. Last winter, a parade of winter storms hit California during La Niña conditions, which are typically drier for the Golden State, the opposite of El Niño.
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More likely, however, are warmer-than-normal conditions, especially in the Pacific Northwest and into Northern and Central California.
Less snow for the northern Rockies, Plains and Great Lakes
Across the northern tier of the United States, El Niño is known for a tendency toward warmer and drier conditions, and that probably means below-normal snowfall for a large swath of the continental United States.
Instead of Arctic air, warmth from the Pacific could dominate, meaning winter storms that develop could contain more rain than snow, Gottschalck said.
However, southward intrusions of polar air can still happen, and outweigh El Niño’s influence. Extreme cold will still occur this winter, but perhaps less often than during more typical winters, Gottschalck said.
Chances for big snowstorms along the East Coast
Some of the East Coast’s most memorable and crushing snowstorms in recent history have occurred during El Niño conditions, including back-to-back blizzards in February 2010 and a single blockbuster storm in January 2016. That is associated with a flow of Pacific moisture across the southern United States, which can create historic snowfall when steered up the Atlantic coast and toward Arctic air.
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Those conditions are again possible this winter, though they depend on other climatic oscillations, including one over the North Atlantic that determines whether cold air is present over the Northeast.
NOAA expects a slight tendency toward greater-than-normal precipitation along the Acela corridor from Washington to Boston, but Gottschalck stressed it could be because one or two large storms could skew seasonal totals.
“There’s some hope for snow lovers,” he said.
Stormy weather and drought relief in the South
Among the safest bets that NOAA forecasters predict this winter: wet, and at times stormy, conditions from the Gulf Coast, across Florida and into the Carolinas.
That is good news for the lower Mississippi River area, which is facing a second-straight year of drought and dramatically low water levels — a condition that is causing salt water to taint drinking water supplies in some Louisiana communities.
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Brad Pugh, operational drought lead for the climate center, said it could take months of increased precipitation to improve groundwater levels and create more lasting drought relief, however.
“That will be a little slower to recover,” Pugh said.
Warmth in Alaska and drought in Hawaii
A strong likelihood of above-normal temperatures is forecast in Alaska and in the northern Hawaiian islands. An even stronger likelihood, if not near-certainty, of dry conditions is expected across Hawaii.
That could contribute to lingering wildfire risks, conditions that led to deadly fires on Maui in August.
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