Long Island forecast: Dangerous cold, wind chills posing threat for hypothermia, frostbite

Long Islanders are facing a day and night of dangerous cold and hazardous wind chills, conditions the National Weather Service warn can cause hypothermia and frostbite in minutes.

The NWS said the bitter wind chills will continue into early Monday, when temperatures will begin to rise into the 30s.

The cause: An arctic air mass has overspread the tristate area, bringing dangerous subzero wind chills that Sunday morning were estimated to be at least minus 16 in Riverhead and Islip, minus 15 in Syosset and minus 18 at John F. Kennedy Airport in Jamaica, Queens.

Northwest winds will be gusty but not as blustery as on Saturday, when they topped 40 mph in places.

Forecasters expect wind chills of minus 5 to minus 15 Sunday afternoon and overnight into Monday.

Without proper precautions, frostbite and hypothermia are possible in as little as 15 minutes on exposed skin, experts say. 

Poorly insulated water lines along exterior walls could freeze and burst, the weather service said.

Bryan Ramsey, a NWS meteorologist, said Saturday night’s overnight low temperature of 3 degrees in Islip marked the coldest since Feb. 4, 2003. 

"The winds were gusting very strong last night between 35 and 40 mph, so, a couple of gusts were closer to 50, which led to a wind chill being around negative 15 to negative 20 across Long Island," Ramsey said.

The snow blanketing much of Long Island from January’s winter storm might not melt away for some time, he said, with temperatures expected to remain low. "I don’t see it leaving any time soon," Ramsey said. "Who knows, maybe we’ll get another storm."

Most of Long Island was spared a winter storm early Saturday that dumped as much as 7 inches of snow on parts of the East End.

Montauk received 7.3 inches, the weather service said. Sag Harbor got 4.5 inches of snow, North Sea had 4 inches and Orient recorded 2.5 inches. Areas west of Great Peconic Bay saw less than 2 inches of snow, with accumulations falling further westward.

Weather service meteorologist Jim Connolly said wind gusts were more than 40 mph Saturday. 

Connolly urged residents to take precautions if they venture out.

"It’ll be cold, so make sure people are dressed appropriately," he said. "There may be some trouble spots on area roads, especially on the [East End], where the winds will continue to blow off those farms and create some areas of blowing snow."

Blowing and drifting snow can quickly reduce visibility, especially along open stretches of roadway bordered by fields, even after the main snowfall has ended.

The start of the workweek Monday is expected to be a bit warmer on Long Island with a high temperature of about 30 degrees, but with winds of 7 to 10 mph, the wind chill values will be between minus 5 and 5 degrees, according to the weather service.

Warming centers across the Island offer options for those without heat or shelter. The Nassau County warming space, on Old Country Road in Westbury, is activated when the wind chill is at 32 degrees or below for two consecutive hours or longer.

Throughout Suffolk County, various public libraries, senior centers and the Dix Hills Ice Rink will serve as warming centers "during excessive cold conditions," according to the county's website. Before traveling to any site, county officials recommend calling to make sure the center is open.

The Nassau County SPCA is advising pet owners to keep their animals inside this weekend due to the extreme cold.

Newsday’s Sam Kmack and Joshua Needelman contributed to this story.