An unseasonable snowstorm warning has been issued for US East Coast on Halloween weekend, with forecasts of up to 10 inches (25 cm) of early snowfall.
A winter storm warning has been issued by the US National Weather Service (NWS) starting with Saturday morning until Sunday.
The NWS also says travel conditions may be hazardous.
About 10,000 people in Pennsylvania, as well as in Maryland and West Virginia, are without power after heavy snow has begun falling across.
In October 1979, southern New England received a record 7.5 inches of snow.
A region of low pressure brewing off the mid-Atlantic coast is expected to produce heavy, wet snow as it moves north-east, according to the NWS.
The Massachusetts Berkshires, north-western Connecticut and southern New Hampshire could see the most snow.
Big coastal cities are set to be hit, forecasters say, with New York expecting four inches (10 cm) on Saturday, and Boston 3 inches.
Winds along East Coast could reach 45 mph (72km/h), further damaging powerlines, the NWS said.
Connecticut Governor Dannel Malloy has warned some residents could lose power, while NWS meteorologist Bill Simpson said the snowfall could break records.
Mountainous areas in Pennsylvania could see as much as six to 10 inches of snow while more than 6 inches of snow are predicted to fall in Maine on Saturday night.
“This is very, very unusual. It has all the look and feel of a classic mid-winter nor’easter. It’s going to be very dangerous,” John LaCorte, a NWS meteorologist in Pennsylvania told the Associated Press.
John LaCorte added that the last time Pennsylvania saw a major storm so early was in 1972.
In New England it is usual for measurable snow to fall in early December.
Meteorologist Bill Simpson said temperatures could return to normal by the middle of next week.
“This doesn’t mean our winter is going to be terrible. You can’t get any correlation from a two-day event,” Bill Simpson said.