It's one storm after another for much of the US, but the next one's path is uncertain

HOUSTON — Winter's brutal grip on the U.S. East is not letting up, with coming days bringing subfreezing temperatures that will plunge deep into what had been a toasty Florida peninsula and a powerful blizzard forecast that may strike the Atlantic coast.

Deep cold is forecast to stick around at least into the first week of February. Meteorologists are also watching what could become a '' bomb cyclone '' — a quickly intensifying storm that's a winter version of a hurricane — forming off the Carolinas Friday night into Saturday.

''A major winter storm appears to be coming to the Carolinas,'' said meteorologist Peter Mullinax of the National Oceanic and Atmospheric Administration's Weather Prediction Center.

That storm could dump snow — at least 6 inches (15 centimeters) with white-out conditions — in the Carolinas, northern Georgia and southern Virginia. After that, it could turn and plow through the Interstate 95 corridor late Saturday into Sunday to dump loads more snow from Washington to Boston, further paralyzing much of the country. Or it could deliver a glancing blow, mostly striking places like Cape Cod.

Alternatively, it could just veer off harmlessly to sea. Meteorologists and forecast models aren't yet settling on a single outcome.

''The confidence is much higher that in the coastal Carolinas and Virginia that there will be significant snowfall this weekend,'' said James Belanger, vice president for meteorology at the Weather Channel and its parent company. "The real question is going to be the trajectory it takes'' from there.

Private meteorologist Ryan Maue, a former NOAA chief scientist, said for the mid-Atlantic and north it's a ''boom or bust'' situation. ''If it happens (to go along the coast) it's going to be a big-time event."

On Tuesday forecast models were all over the place, from out to sea to inward toward Philadelphia. By Wednesday morning they started to agree that ''we're likely to see some form of a powerful coastal storm somewhere east of North Carolina, off the Delmarva coast, but they still disagree as to where,'' Mullinax said.

Chances of the storm veering away from the East Coast entirely had diminished Wednesday morning, but hadn't disappeared altogether, Mullinax said.

Of all the options, ''from D.C. up to New York is probably the most unclear,'' Mullinax said. He said a mere 50-mile (80-kilometer) difference in the storm's center will be critical. AccuWeather Senior Meteorologist Dan Pydynowski said it may be hard for the southern mid-Atlantic to avoid some kind of snow, whether a little or a lot.

This storm will blow harder than the last one

This weekend's storm will differ from the previous storm, which started with moist air from the Pacific that combined with a deep plunge of Arctic air from an elongated polar vortex supplemented by more moisture from the south and east, meteorologists said. The last storm had little wind. This one will generate high winds, even if the snow misses the Washington area, generating gusts that could still reach 40 mph (65 kph), plunging wind chills near subzero Fahrenheit (minus 18 Celsius), Mullinax said.

''This is what we'd consider more of a classic nor'easter,'' Belanger said, describing a storm forming around the U.S. Gulf Coast crossing into the Atlantic and going up that coast.

Frigid air and warm water combine to make strong storm

In this case, one key is warmer-than-normal water in the Gulf of Mexico — partly from human-caused climate change — and the always toasty Atlantic Gulf Stream, said Bernadette Woods Placky, chief meteorologist for the nonprofit Climate Central.

When that happens the storm ''pulls in more moisture and it gives it more strength,'' she said.

Once the core of the storm nears the Carolinas its pressure will drop tremendously, enough to qualify for what meteorologists call ''bombogenesis'' or ''a bomb cyclone,'' That will give it the effect of a moderate-strength hurricane, including huge winds, but in the winter, Maue and Belanger said.

Arctic chill sticks around and goes further south

What is more certain is that the Arctic chill in the Midwest and East will continue through mid-February, with only slight warmups that would still be below normal, meteorologists said.

And this new weekend storm ''is going to take that cold and it's going to spill right down the heart of the Florida peninsula," Pydynowski said. Orlando is forecast to go well below freezing and only have a high of 48 F (9 C), smashing temperature records, while even Miami and Key West will flirt with record cold Sunday and Monday, meteorologists said.

The outlook for Florida was cold enough to raise concerns about damage to the state's citrus and strawberries.

''We're going into a brutally cold period,'' Maue said.

After this weekend storm, long-range models see another one at the end of the first week of February, Maue said. Meteorologists see the East stuck in a pattern of bitter cold and snowstorms because of the plunging Arctic air and warm water.

East Coast snowstorms don't happen too often, but ''when it happens, it happens in bunches," said former National Weather Service director Louis Uccellini, who has written meteorology textbooks on winter snowstorms.

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