Thursday morning will briefly feel like winter — shortly before dawn the temperature in Islip was 24 degrees — but by about midday the sun will have raised thermometers to 44 degrees and a high for the day of 51 is expected.
And that, the National Weather Service’s Islip office said, will mark the start of a sunny, warm stretch that will run through the weekend and only possibly ends on Monday, when there is a 40% chance of rain.
The frigid air greeting anyone outside early Thursday is just two degrees above the record in Islip for this day in November. It is not that uncommon for November’s temperatures to bounce around as they have recently, weather service meteorologist Brian Ciemnecki said by telephone.
"The cold is not something that’s abnormal this time of year. Usually it comes in for a few days and starts warming up again," Ciemnecki said.
Thursday’s fair weather is partly courtesy of a high pressure area over the Carolinas that will head out to sea.
On Long Island, the weather service said, "Winds will generally be 10 to 15 mph, with some gusts along the coast up to 25 mph by late afternoon."
Those breezes, the weather service added, will bring "more seasonable temperatures into the region, with highs in the middle to upper 40s and lower 50s along the coast."
High pressure delivers fair weather as the air dries as it falls toward the ground. The rising air of low pressure systems, which exert less force on the Earth’s surface, can cause vapor to condense, creating clouds and showers, scientists say.
The nighttime low on Thursday also will be much milder, at 47 degrees.
And Friday should bring more sunshine with a warm daytime high of 59 degrees — around six degrees above the mean maximum temperature recorded during November in Islip since 1963, when the weather service records begin. The typical low is 37.1 degrees.
After another system helps bring a cold front that arrives and departs Friday night, the weather service said, "High pressure should then follow and build north of the area on Saturday providing a dry and fairly mild start to the weekend."
Both Saturday and Sunday should be bright and clear with highs during the day of just below 60 degrees.
Monday will be just as warm though there may be showers. Tuesday will be sunny, though colder, with a daytime high of just 49 degrees. Wednesday may see more clouds and showers with a high during the day of 51 degrees, the weather service said.