Atmospheric river and potential bomb cyclone bring chaotic winter weather to the East Coast

PORTLAND, Maine (AP) — The U.S. East Coast began a whiplash-inducing patch of weather Wednesday that was rainy, windy and potentially dangerous, partly due to an atmospheric river and the developing bomb cyclone.

Places like western Maine could see freezing rain, downpours, unusually high temperatures and damaging winds — all in the span of a day, said Derek Schroeter, a forecaster with the National Weather Service.

Heavy rain and strong winds will continue in many areas until Wednesday night and flooding is possible in some places, forecasters said. Utilities were also preparing for possible power outages due to damage caused by winds that could exceed 60 miles per hour in areas.

This December 10, 2024 image from the National Oceanic and Atmospheric Administration... — This December 10, 2024 image provided by the National Oceanic and Atmospheric Administration (NOAA) shows the U.S. Atlantic east coast.(NOAA via AP)

One of the most important factors that determine the weather is an atmospheric riverwhich is a long band of water vapor that can transport moisture from the tropics to more northern areas, said Schroeter, based in Gray, Maine.

The storm has the ability to hit New England hard because it can tap moisture from the Atlantic Ocean off the coast of the southeastern US, and transport them to places like Maine. The state was preparing for a “multi-sided storm” that could bring two to three inches of rain in some areas, Schroeter said.

The region experienced a combination of fog and light freezing rain Tuesday night into early Wednesday.

Schroeter said “we will be watching for the possibility of flash flooding and sharp river rises as temperatures rise into the 50s (10-15 degrees Celsius).”

Forecasters also said the storm had the potential to involve what meteorologists call a process bombogenesisor a ‘bomb cyclone’. That is the rapid intensification of a cyclone in a short period of time, and it has the potential to cause heavy rainfall.

Parts of the Northeast were already preparing for bad weather.

In New Hampshire, the Mount Washington Avalanche Center issued a special bulletin Wednesday for the Presidential Range of Mountains, which has seen significant snowfall over the past two weeks.

“Heavy rainfall can cause dangerous and unpredictable avalanche conditions on steep, snow-covered slopes,” the report said, creating unsafe conditions at stream crossings, ski and hiking trails and bridges.

In Maine, some schools were delayed on Tuesday, which started with several inches of snow. A flood watch for Vermont runs from Wednesday afternoon through Thursday morning.

The city of Montpelier, Vermont, advised residents to prepare for mild floods in the area and to lift objects in basements and low areas prone to flooding. The city said Tuesday that it has been in contact with the National Weather Service and Vermont Dam Safety and will “actively monitor river levels as this storm passes.”

Ski resorts across the Northeast prepared visitors for a potentially messy day on Wednesday. Stratton Mountain Resort, in southern Vermont, posted on its website that customers should “make sure to pack your Gore-Tex gear because it will get wet.”

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Associated Press writers Lisa Rathke in Marshfield, Vermont, and Kathy McCormack in Concord, New Hampshire, contributed to this story.