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(CNN) --
The path this weekend for a powerful bomb cyclone is becoming clearer as 75 million people from the Mid-Atlantic states to New England face a potentially dangerous threat of heavy snow and hurricane-force winds, according to the forecasts.
More than 75 million people in the eastern US are under winter weather advisories from Kentucky to North Carolina to Maine.
The National Weather Service issued blizzard warnings for 4 million people along coastal areas from Maine south to Massachusetts and New Jersey south to Maryland. Includes Boston, Atlantic City, Portland, Maine and Ocean City, Maryland, for snow blown by high winds. This will create bleaching conditions and make travel difficult or impossible. Winter storm warnings were also issued for New York City and Philadelphia. Heavy snowfall and wind gusts are expected in these areas.
The storm is expected to form this Friday off the coast of the Carolinas and then move north up the East Coast overnight into Saturday as it rapidly strengthens in a process called bombogenesis.
Also known as a bomb cyclone, the process occurs when a storm drops a certain amount of atmospheric pressure over a 24-hour period.
Eastern Massachusetts, including Boston and Rhode Island, could see 5 to 24 inches of snow combined with wind gusts of up to 60 mph, according to multiple forecast models.
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"The snow drift appears likely to result in significantly reduced or near-zero visibilities at times for southeastern Massachusetts. At this time, we are more confident in blowing conditions developing from Plymouth County to the Cape/Islands." , the National Weather Service office in Boston warned early Friday.
In addition, parts of the Mid-Atlantic and New England coasts face the threat of a dangerous blizzard, which could pack 12 inches or more of snow, according to the Weather Service's Weather Prediction Center.
A blizzard occurs when snow is joined by winds gusting over 35 mph for more than three hours and creates visibility of less than a quarter mile.
"Blackout conditions could create nearly impossible travel, while high winds will likely result in scattered power outages and some damage," the Weather Prediction Center said.
A bomb cyclone with the power of a hurricane will bring snow and blizzard to cities in the northeastern US.
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The bomb cyclone will bring snow, wind and coastal flooding in the northwest
The storm is expected to unleash a double whammy of heavy snow and strong winds in parts of the Northeast, but exactly which parts of the region remain in question.
"This storm is likely to strengthen at a rate and intensity equivalent to only the most powerful hurricanes, so this storm's high-level potential cannot be overstated," said CNN Meteorologist Brandon Miller.
"But with nor'easters, like real estate, it's going to come down to location, location, location."
Parts of northeastern North Carolina and southeastern Virginia could see up to 3 inches of snow, with winds up to 35 mph, according to the National Weather Service.
And once the storm reaches the East Coast, it can dump up to 14 inches of snow in parts of Connecticut and New York, where wind gusts can reach up to 55 mph, the NWS predicted.
But forecast models remained uncertain on Thursday.
In neighboring New Jersey, northeastern parts of the state may see up to 9 inches of snow as wind gusts reach 50 mph, the NWS said.
The bomb cyclone could also dump up to 8 inches of snow on Philadelphia, while parts of Delaware could see up to 10 inches of snow, according to multiple forecast models.
Coastal flooding and extremely cold temperatures are a possibility, the Weather Prediction Center warned.
And the stronger the storm, the greater the surge of water along the coast.
"Coastal flooding is a concern thanks to astronomically high tides on Saturday," NWS Boston said.
"The combination of strong northeasterly winds and high seas will bring storm surge which, if it coincides with high tide, will cause minor to moderate coastal flooding."
The difference in storm timing, even as little as six hours, would make a big difference in the impact of coastal flooding and erosion concerns.
Fog covers the lower Manhattan skyline on January 25 as seen from Jersey City, New Jersey. (Credit: Gary Hershorn/Getty Images)
Forecast for New York City remains uncertain
And while the storm's path has become clearer over the past 24 hours, its impact in some areas is still unpredictable.
A European forecast model shows New York City teetering on the snow/no-snow divide, but still predicting a lot of snow.
The American model shows almost nothing for the city.
A third model indicates a foot or more of snow.
The NWS forecast as of early Friday is between 6 and 23 centimeters of snow, with wind gusts up to 80 km/h.
However, it says there is a 10% chance the bomb cyclone will dump more than 17 inches of snow, while giving a 10% chance no snow will fall.
And direction is playing a vital role in forecasting this storm, noted CNN meteorologist Chad Myers.
"It's like a bowling ball going right down the middle or slightly off center. You can get a 7-10 split or a strike just an inch apart," Myers said.
"I think the models will come together as we get closer to the event."
-- CNN's Judson Jones and Robert Shackelford contributed to this report.
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