Northeast winter storm to usher in an extreme weather week

The long-running snow drought from Washington to Boston is likely to end in some areas as a winter storm develops and intensifies as it moves close to this region over the weekend.

Threat level: This storm will be just the start of an extreme weather week across the country, with the National Weather Service already sounding alarms about a follow-up storm and a

• The weekend event will bring mainly rain to D.C., Baltimore and Philadelphia, with slightly more wet snow falling in New York City.
• However, the region from Hartford to Providence to Boston could pick up 8 to 12 inches by the time the storm ends late Sunday, according to the National Weather Service.

The big picture: The storm system likely to affect the heavily populated Amtrak Acela corridor is projected to spin up from a combination of atmospheric disturbances moving across the country.

• Into the weekend, these will tap into moisture from the Gulf of Mexico and the Atlantic Ocean, as well as jet stream energy aloft.
• Exactly where and how these ingredients come together, though, will determine where the heaviest precipitation falls.
• Snow, sleet and rain are expected to overspread the mid-Atlantic region on Saturday, quickly changing to rain from Washington to Philadelphia. A coating to an inch of snow is possible in these cities on the front and back sides of the storm, with moderate to heavy rain falling in between.
• Areas well to the north and west of the Washington to New York City region could see 6 to 10 inches of snow, with isolated amounts as high as 12 to 14 inches.

What we’re watching: By Sunday, the winter storm is likely to prove disruptive for travel from central and eastern Pennsylvania northeastward to the Hudson Valley on across southern New England.

• Airport delays are likely in the big cities due to mixed precipitation, low clouds and gusty winds. This will especially be the case in Boston, where winds could gust to 50 mph on Sunday, according to the National Weather Service’s Boston forecast office.
• In a forecast discussion Friday morning, the NWS Boston office noted that recent computer model trends show an increasing probability of heavy snow for downtown Boston and Providence.

Context: The region that will be affected by this snowstorm has not seen more than an inch or two of snow in as long as two years.

• For example, in New York City, Central Park last saw an inch of snow in Feb., 2022. And in Boston, the biggest snowstorm last winter was just 3.5 inches.
• The Boston and New York City streaks have the greatest chance of being broken.
• El Niño winters can bring significant East Coast snowstorms, particularly across the mid-Atlantic. So if this one is mostly a rain event, there may be more chances for snow ahead.

The intrigue: While the NWS is busy forecasting this storm, its experts are already gearing up for what could be an unusually intense winter weather event early next week, which this time would bring the potential for blizzard conditions to parts of the Plains and Midwest.

• The same weather system could spark severe thunderstorms across the Southeast, along with heavy rain and damaging winds in New England.
• Computer model projections show the potential for widespread damaging winds across multiple states as the area of low pressure quickly intensifies and moves across the Great Lakes region and into Canada.
• This blizzard may drag extremely cold air associated with a piece of the tropospheric polar vortex behind it, which would pinwheel south from Canada.
• While the intensity of the cold is unclear — some models are showing the potential for temperatures to plunge 50°F below average for mid-January across the Plains and West — a shift to colder temperatures is likely in the Lower 48 states.

The bottom line: Much of the Lower 48 states will be affected by extreme weather in the next week to 10 days.

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