Long Island weather: Cold and windy, with highs in the 40s

The current cold snap will last through the Thanksgiving Day holiday next week — but it will be mostly sunny, the National Weather Service said.

Temperatures were expected to drop all the way down to about 29 degrees Friday night.

Saturday will be sunny but the high temperature will only be about 43 degrees with wind chill values between 25 and 35, the weather service said Friday evening. A west wind will blow Saturday at 7 to 14 mph., the forecast said.

The normal high temperature for the date in Islip is 52 degrees.

Saturday night should be mostly clear, with a low of around 30 degrees.

The temperature on Sunday is only expected to reach near 40 degrees under sunny skies.

Colder than usual

A high-pressure weather pattern, in which falling air keeps clouds from forming, is developing to the south of the New York metro area, and will dominate the weather over the next week.

The switch between clear skies and potentially light rain is driven by “multiple weak cold fronts/surface troughs swinging through while high pressure weakens each time,” the weather service explained.

“Normal high temperatures for this time of the year are in the lower to mid-50s,” according to the weather service.

Daytime temperatures over the next week, however, will not make it out of the 40s, except perhaps on Wednesday.

At night, freezing temperatures are predicted, with Sunday night’s forecast low of 26 degrees to be the coldest.

“Highs on Saturday don't make it out of the upper 30s and lower 40s for all except Long Island, where a warmer southwesterly flow off the water should allow highs to reach the mid- to upper 40s,” the weather service said.

And Sunday will be even chillier as a shortwave trough, or a low pressure system, “pivots through aloft as an associated cold front sends a reinforcing shot of cold air," the weather service said.

Gusts of wind could reach 34 mph, and wind chills in the 20s are expected throughout the day.

Monday’s winds will be calmer, and high pressure systems approaching from the south and then the northwest should keep the region rain-free, at least through the day on Thursday.

The weather service said: “Any system that would bring precipitation to the area looks to be outside of the long-term period and have kept Thursday dry, bringing in a slight chance of probability of precipitation Thursday night.”