A winter storm is expected to wallop the New York City region starting late Thursday — with 3 to 6 inches of snow expected to make for a tough Friday morning commute, forecasters said.

Snow is expected to start falling in the tri-state area by midnight, with conditions “quickly deteriorating” overnight and into Friday’s morning rush hour, making for potentially dangerous travel, AccuWeather meteorologist Tyler Roys told The Post on Thursday.

Up to 6 inches may fall across the region, with the highest totals expected south and east of the Big Apple. The heaviest snowfall will come between 4 and 7 a.m. Friday — and taper off by midmorning, Roys said. Wind gusts could also reach up to 35 mph.

“It’s going to be a wet snow,” Roys said early Thursday. “Tomorrow’s commute is going to be very difficult. If people can stay off the roads until at least midmorning, it’ll make life easier for everyone.”

Commuters should heed the warning, Roys said, or potentially risk being stuck on roadways like the hundreds of drivers, including Sen. Tim Kaine, who were stranded overnight Monday on a Virginia highway after a severe snowstorm battered the region.

“Overall, if people can stay off the roads, the morning commute likely won’t turn into what happened in Virginia earlier this week,” Roys said.

Virginia declared a state of emergency late Wednesday ahead of Friday’s expected snowfall in the region, which could dump another 6 inches of snow in some parts of the state. Washington, DC, meanwhile, could see up to 3 more inches on top of the 11 that fell starting Monday, snarling traffic along a 50-mile stretch of Interstate 95.

The National Weather Service in New York, meanwhile, has issued a winter weather advisory for the tri-state region from 12 a.m. through 12 p.m. Friday.

Forecasters predict 2 to 4 inches in Orange and Putnam counties, with 4 to 6 inches expected in Long Island and southern Connecticut.

In New Jersey, 3 to 6 inches is expected in the bulk of the state, while northwest portions should get 1 to 3 inches, Roys said.

Some spots across the region, especially south and east of New York City, may get up to 7 or 8 inches, but they’ll be “far and few between,” Roys said.

Friday’s quick-moving storm will also drop about 3 to 6 inches of snow in Philadelphia and Boston, with totals in Beantown expected to be closer to the higher amount, AccuWeather meteorologist Tom Kines told The Post. 

The snowfall is expected to last about six hours — at about an 1 1/2 inch per hour in New York City and elsewhere in the region, Kines said.

“There will probably be a time when it’s coming down pretty hard,” he added. “It’s going to feel pretty brutal out there.”

Once out of the area, sunshine will return Friday afternoon, but temps in the Northeast will stay in the 30s before plunging below freezing overnight. 

Saturday will be “much more tolerable,” Kines said, with abundant sun and temperatures around the freezing mark by afternoon. Rain could move into the Northeast by Sunday, however, before conditions turn colder on Monday and Tuesday.

The looming Northeast storm that blanketed parts of the South Thursday has already led Boston Public Schools to close all schools Friday, while classes in Philadelphia will move to virtual instruction.

A message seeking comment from NYC’s Department of Education, which serves 1.1 million students in more than 1,800 schools, was not immediately returned.

Late Wednesday, the NYC Department of Sanitation issued a “snow alert” starting at 7 p.m. Thursday in response to 6 inches expected. Parking meters will remain in effect, but alternate side parking had already been suspended due to Three Kings Day, the agency said.

Friday’s precipitation will arrive just days after a storm Monday dumped up to 14 inches across some parts of southern New Jersey, including in Cape May County.