Long Island's first heat wave of the year became official shortly before noon Tuesday when the temperature hit 90 for the third day in a row at Long Island MacArthur Airport in Ronkonkoma.
Three consecutive days of 90 degrees or above translates into a heat wave, according to the National Weather Service.
What's more, as of shortly before 4 p.m., the record high for the day -- 93 degrees set in 1999 -- was broken as the temperature at the airport hit 94 degrees, with a heat index of 95, meaning that's how hot it felt due to humidity, the weather service said.
Temperatures also hit 93 in Farmingdale and Shirley, with heat indexes of 95 and 96, respectively.
A heat advisory was in effect Tuesday for Nassau County and western Suffolk County, with heat index expectations of 99 and up, said Lauren Nash, weather service meteorologist, based in Upton. The heat index was slightly less, however, due to less moisture in the air than expected. But it was enough that Suffolk police reported road buckling from the heat on the LIE at exit 68.
Thanks to a ridge of high pressure stalled over the area, "oppressive heat and humidity" are in the forecast through Friday, possibly Saturday, depending on cloud cover from a cold front expected to bring relief, the weather service said. The front could also bring heavy rain and strong winds.
Hours at Jones Beach, Robert Moses, Heckscher, Hither Hills and Sunken Meadow state parks are extended to 8 p.m. through Friday, officials said. That also goes for hours at the Jones Beach West Bathhouse pool.
Suffolk is also opening cooling centers in Brentwood, Selden and Riverhead Wednesday through 8 p.m., officials said. And hours at Nassau's major outdoor swimming pools were extended, according to an announcement.
Most Long Island towns announced special measures to deal with the heat, including extended pool hours and the opening of cooling centers.
With the heat turned up, the Long Island Power Authority's peak load was 5,446 megawatts as of 5 p.m. Tuesday, well below its all-time high of more than 5,900 megawatts, but continuing a week of near-record demand. LIPA has more than 6,300 megawatts of capacity to meet that demand.
LIPA hit a peak load of 5,552 megawatts Monday, the sixth highest in its history.
According to the New York Independent System Operator, which manages New York energy markets, the LIPA system hit its peak Monday at around 4:50 p.m.
LIPA said that while it has "more than sufficient capacity" to meet demand, it blamed the "unusual strain" of high use for the "localized outages."
With Gary Dymski