Long Island forecast: Coldest temps season arrive Monday night, stay through Wednesday morning

An arctic air mass that arrived Monday will stay locked on Long Island through Tuesday night, bringing the coldest temperatures of the season and subzero wind chills, the National Weather Service said.

Monday's overnight will bring wind chills of nearly 0 to 5 degrees below zero that will last through Tuesday morning, the weather service said — a brutal combination of temperatures in the teens and a northwest wind of between 15 and 20 mph.

"If you need to be outside, be prepared for the wind and cold, and dress in layers and wear a hat, heavy coat, as well as gloves or mittens. Frostbite can occur in a short amount of time, so dress in layers and make sure all exposed skin is protected," the weather service advised.

Tuesday afternoon, there isn't much change in the deep chill. The high will be just 19 degrees and the wind chill will be between zero and 10 degrees, forecasters said. Winds should calm down overnight but the wind chills will still be a factor — between zero and 10.

"For much of the Northeast and New England, these frigid temperatures will remain locked over the region into Wednesday morning as a strong high pressure system slowly swings over the eastern United States," it added.

Wednesday does eventually bring a warmup, a high of about 38 degrees by the afternoon but a gusty breeze of up to 25 mph will still keep the wind chills in play.

Thursday and Friday will be sunny with relatively mild temperatures close to 40 in daytime highs, the weather service said. Nighttime lows will be very cold however: about 25 degrees for Thursday and just 12 for Friday.

But Saturday, the high will be just barely freezing and there is a 30% chance of snow at night. Sunday has a similar high and chances for snow showers during the afternoon.

Monday, Martin Luther King Day, is predicted to be partly sunny with a high of 34 degrees, the weather service said.

With Joan Gralla