Long Island weather: Thursday brings relief from the heat wave, dropping into the 70s, chance for showers overnight

Relief arrives Thursday from the record-breaking three-day heat wave that captured Long Island this week, with scattered showers and a cold front expected to move into the region overnight Wednesday, ushering in cooler conditions.

"Expect some scattered showers and storms later tonight and into a portion of tomorrow," Jay Engle, a meteorologist with the National Weather Service, said Wednesday evening. "We’re having a cold front coming in from the Great Lakes and Canada."

Temperatures were forecast to drop into the mid-70s Thursday, and stay in that range through the weekend, as unsettled weather brings chances of showers through Saturday, the weather service said. Next week brings a warmup, but only to the mid-80s, which is considered seasonable for this time of year, and more chances for rain.

Once again, Long Island hit record-breaking temperatures on Wednesday when Islip reached a high of 98 degrees. The last record for that day in Islip was 92 degrees in 2003. Temperatures tied or exceeded records in Central Park, and at both JFK and LaGuardia airports, the weather service said. 

"Overall, temperatures did get very hot between 95 and 100 degrees across Nassau and Suffolk counties," said Bryan Ramsey, a meteorologist with the National Weather Service.

The Department of Environmental Conservation had issued an air quality alert for Wednesday from 11 a.m. until 11 p.m. due to ground level ozone. The ozone level was forecast to go down for Thursday, according to the state Department of Environmental Conservation.

Ozone is the main component of "smog" — a mixture of air pollutants produced when sunlight meets air contaminants from automobile exhausts and other sources, the Suffolk County Health Department said. 

Tuesday’s temperatures broke records, as Islip hit 100 degrees around 2:50 p.m., then went on to hit 101. It was the hottest day on the Island since it hit 101 on July 6, 2010 and the hottest day in June ever on Long Island, the weather service said.

Long Island was also under an extreme heat advisory on Tuesday due to the heat value index reaching 105 degrees or higher, the service said. While temperatures dropped slightly on Wednesday, heat value indexes remained unusually high, nearing 100 degrees, dangerous to anyone without cooling or hydration, the weather service said.

The heat index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.

Long Island saw widely scattered power outages overnight into Wednesday morning. At 7 p.m. Wednesday, more than 1,000 customers were without power.

PSEG Long Island issued a statement urging its customers to cut back on electricity use to help ease the stress on their system. It recommended that its customers turn off nonessential electronics and appliances and run major appliances, such as washing machines, in the morning or late evening.

"Four consecutive days of extreme heat puts a great deal of physical strain on lines, transformers and other common pieces of equipment that make up our energy grid and have been handling peak levels of demand," said Michael Sullivan, PSEG Long Island’s vice president of Electric Operations. "While we expect to have sufficient electrical capacity to meet the demand, we urge customers to reduce their energy usage to help protect the grid and limit the number of scattered, heat-related outages that occur today."

Newsday's Bahar Ostadan contributed to the story.