Long Island forecast: Heat and humidity continue, with thunderstorms again likely Friday evening

Long Islanders are in the midst of another day of hot and humid conditions Friday afternoon, and can expect another round of thunderstorms, as a heat advisory remains in effect through 8 p.m.

The National Weather Service said the heat index is again reaching 100 degrees on Friday, following similar conditions on Thursday. Areas nearer to New York City can expect the highest temperatures, the service said.

From 6 to 9 p.m., conditions "are favorable" for thunderstorms to develop on Long Island, but precisely where remains unclear, weather service meteorologist David Stark told Newsday. A severe thunderstorm watch remains in effect through 9 p.m.

"As far as the main threat, it's damaging wind gusts," Stark said. "Obviously any thunderstorm could produce thunder and lightning and a brief, heavy rainfall, but the main concern is damaging winds."

Thursday night, thunderstorms brought winds gusts as high as 66 mph, which battered northern Suffolk areas, including Rocky Point and Wading River, Stark said. Damage reports detailing fallen trees and powerlines were "fairly widespread" in those and surrounding communities.

"Something like that is certainly possible again," he added of Friday night. "We can't really say for sure what part of the Island, if any, would see it."

The weather service has also warned that storms could produce hail and localized flash flooding.

Highs reached the upper 90s across Long Island Friday afternoon, with humidity to blame for it feeling hotter, the service said. As of nearly 5 p.m., the temperature had dropped a couple of degrees, to 91, after having reached 93 about an hour before, according to the weather service. But the heat index remained at 97. If confirmed, Friday's high would beat the 91 degrees for June 12 at MacArthur Airport, reached in 2017.

Thursday's recorded high of 92 degrees at MacArthur came close to its record high of 93 degrees, reached in 1973. 

The state Department of Environmental Conservation issued an air quality alert for Friday until 11 p.m. and recommended limiting strenuous outdoor activities, especially for vulnerable populations.

"People who may be especially sensitive to the effects of elevated levels of pollutants include the very young, and those with preexisting respiratory problems such as asthma or heart disease," the service said. "Those with symptoms should consider consulting their personal physician."Long Island should also expect showers and possible thunderstorms beginning Friday afternoon into the evening.

A localized flash flood threat is in effect, with the weather service predicting 1 to 2 inches per hour. 

The service also said to be aware of wind gusts that could top 58 mph.

Thursday's storms left Rocky Point resident Lori Hebert with a tree down on her Lexus SUV by her home on Zenith Road. Hebert, who has lived there since 2019, was working with neighbors with chainsaws to clear it.

She said she was used to sudden storms and fallen tree limbs in Rocky Point but has previously escaped major damage.

The tree shattered her windshield and crushed the hood of her car but only clipped the gutter of her house.

"It was sudden. I was going to go out and got a text to stay away from windows with 80 mph winds," Hebert said. "I heard a thunderclap and a really loud crash within minutes. I'm just glad it wasn’t worse and I wasn’t in the driveway."

Hebert said it was not as bad as the 2024 storm that left her without power for about a week.

She said she had recently had other trees removed from her property out of fear they might have toppled onto her house.

"I didn’t think about it. It just seemed so sudden and went away quickly, and then it was gone," Hebert said. "It’s Rocky Point so there are a lot of trees and when it’s windy, it's really windy up on the hills, so I'm used to hearing the wind rustle the branches."

With another storm possible Friday, she said she was hoping to avoid further damage. "I’m hoping it's the old saying, 'lightning only strikes once,' " Hebert said, although the tree was apparently felled by wind rather than by lightning.

Just after 6 p.m. on Thursday, wind gusts up to 66 mph hit central Suffolk County, causing "extensive damage"  from downed trees and wires to areas like Shoreham, Rocky Point, Wading River, Ridge, Middle Island, Manorville, Shirley-Mastic and Mastic Beach, service meteorologist James Connolly said. 

"PSEG Long Island is responding to severe thunderstorms that have caused power outages across our service area," a statement on the PSEG website said. "We understand how difficult it is to be without power, and our crews are working around the clock to restore service as safely and quickly as possible. Restoration efforts will continue until all customers have been restored."

A cold front moving in on Friday will break the humid conditions, the service said — but not the heat. 

Saturday and Sunday will see high temperatures in the upper 80s to low 90s with mostly dry conditions.

Following showers late Sunday into early Monday, temperatures will drop significantly most of next week, with highs expected in the upper 70s to low 80s.