As unsettled, showery weather moves out this weekend, it's looking like Long Islanders are facing their first heat wave of the year next week, forecasters say.

"A big high-pressure area is going to settle over the eastern third of the country," expected to bring high temperatures in the low 90s, but feeling hotter than that thanks to the humidity, said Tim Morrin, meteorologist with the National Weather Service in Upton.

The high temperature at Long Island MacArthur Airport in Ronkonkoma was forecast for 89 Monday, with a heat index as high as 96, he said, as of Friday's forecast. Tuesday's temperature and heat index were forecast for 91 and 95, respectively; Wednesday's, 91 and 97; and Thursday's 93, with an index of 98 up to noontime, he said.

Assuming the forecast holds, and Long Island experiences three consecutive days of 90-degree or higher temperatures, this would mark the first official heat wave of 2013, Morrin said. Two heat waves have been recorded at Central Park -- July 5-7 and May 30-June 1 -- said Dan Hofmann, also a meteorologist in Upton.

Indeed, "the main story for this period will be the building heat," the weather service said, starting Sunday, when temperatures on Long Island are expected to head up from the high 70s to the upper 80s.

Figures forecast for Central Park next week are just slightly higher than those expected on Long Island, Morrin said, indicating "a pretty homogeneous air flow from the west." Those in northwestern Nassau could see similarly higher temperatures than those indicated for the airport, he said. And, moving toward the South Shore, especially along the South Fork, temperatures may be "a few degrees cooler," Morrin said, "but it will still be no picnic, comfort wise."

Ultimately, much depends on the presence and location of sea breezes and "the recipients of sea breezes," he said.

The Long Island Power Authority, meanwhile, said it is ready for the hot temperatures.

The NewsdayTV team looks at the most wonderful time of the year and the traditions that make it special on LI.  Credit: Newsday

'Tis the season for the NewsdayTV Holiday Show! The NewsdayTV team looks at the most wonderful time of the year and the traditions that make it special on LI.

The NewsdayTV team looks at the most wonderful time of the year and the traditions that make it special on LI.  Credit: Newsday

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