Blizzard warnings were issued Saturday for New York City, New Jersey and coastal communities along the east coast for a late-winter storm set to arrive on Sunday that could dump more than a foot of snow and bring wind gusts of more than 55mph.

The blizzard warning for New York City is the first since 2017 and comes as parts of the city are still dotted with hillocks of ice – leftovers from the previous major snowstorm nearly a month ago.

The National Weather Service increased its assessment of the severity of the storm, saying it anticipated 1ft to 2 ft of snow for New York City, Long Island, southern Connecticut and coastal communities in New Jersey and Delaware. Flooding was also possible in parts of New York and New Jersey, the weather service said.

“While we do get plenty of these nor’easters that produce heavy snow and strong impacts, it’s been several years since we saw one of this magnitude across this large of a region in this very populated part of the country,” said Cody Snell, a meteorologist at the service’s Weather Prediction Center.

New York City mayor Zohran Mamdani said at a news conference Saturday the city could get up to 20in. The blizzard warning takes effect at 6am Sunday and lasts through 6pm Monday.

“We are now expecting between 13 to 17 inches of snow, but there is a slight chance we may see up to 20 inches, if not more,” Mamdani said, adding that efforts to get unhoused New Yorkers off the streets and into shelters would begin Saturday afternoon.

At least 19 people were found dead outdoors in the city after temperatures plunged on 19 January and remained below freezing for 10 consecutive days. At least 15 of the victims are believed to have died due to hypothermia.

The NWS’s Snell said the storm will arrive Sunday morning in areas around Washington DC, before stretching toward Philadelphia and New York City and reaching Boston late Monday evening.

The weather service warned that the storm will “make travel dangerous, if not impossible. Scattered downed tree limbs and power outages possible due to snow load and strong winds.”

With the arrival of the blizzard coinciding with the start of thew work week, Mamdani said he was asking New Yorkers “to stay inside and stay off the roads for your safety. These have the potential to be even more hazardous conditions than we faced the last time around.”

On Saturday, officials in Atlantic City, New Jersey, urged residents and casino visitors to stay off streets during the storm, especially in low-lying neighborhoods prone to flooding.

“I could go on and on probably with a good two dozen streets where we know we will get water and there will be snow on top of that,” said Scott Evans, the city’s fire chief and emergency management coordinator. “So you won’t be able to see it until it’s too late, so therefore please stay at home.”