Long Island forecast: Dangerous cold, light snowfall Friday and into weekend

Another blast of arctic air will bring dangerous cold back to Long Island Friday night and this weekend.

The National Weather Service has issued an extreme cold watch for Long Island and New York City, in effect from 6 p.m. Saturday through 1 p.m. Sunday — warning that "dangerously cold" wind chills making it feel like 15 below zero are possible.

"The cold wind chills could result in hypothermia if precautions are not taken," the weather service bulletin reads. "Dress in layers, including a hat, face mask, and gloves if you must go outside."

The weather service also warned of the potential for freezing pipes, including in-ground and above-ground sprinkler systems, and also urged owners to keep pets indoors "as much as possible."

Temperatures hovered in the upper 20s Thursday — in what seemed like relatively balmy weather — and likely will be about the same Friday, according to the weather service. But the combination of subfreezing temperatures and strong, gusting winds could result in wind-chill values between 15 and 20 degrees Friday night — with a major drop off coming in the evening Saturday.

Light snow is also expected Friday night and Saturday, accumulating to a couple of inches or less. But the weather service warned in its Thursday afternoon forecast: "The more impactful weather will be the cold air and strong winds, leading to potentially dangerous wind chills late day Saturday into Saturday night."

The agency said the potential snowfall and temperatures Saturday falling to as low as 4 degrees could result in Arctic-like conditions, with wind gusts as strong as 41 mph leading to the potential of wind-chill values of minus-15 degrees.

Predicted high temperatures in the teens won't help the situation Sunday, the weather service said, and wind chills at night will feel like zero to 10 below. Neither will single-digit temperatures predicted Sunday night into Monday, when temperatures will improve slightly. But the mercury won't break the freezing mark on Long Island until Wednesday, with a high of 36 and a chance of rain.. 

The weather service's bulletin reminded people that despite the frigid weather, they should never use generators or grills indoors due to the potential for toxic fumes.

The weather service has also issued a gale watch for all Long Island waters for Saturday — advising all mariners to consider altering plans to avoid any potential hazardous conditions.

"Remain in port, seek safe harbor, alter course, and/or secure the vessel for severe wind and seas," that bulletin advised, adding: "Operating a vessel in heavy freezing spray is hazardous."