Parts of Long Island could experience a heat wave Monday if the weekend’s blazing temperatures continue.

The high at MacArthur Airport in Islip reached 96 degrees Saturday and 90 degrees Sunday.

Monday’s forecast calls for the upper 80s at Islip and lower 90s for parts of Nassau County, said meteorologist Joe Pollina of the National Weather Service in Upton.

Cooler conditions are expected on the North and South forks, which are expected to stay below the 90s, he said.

A heat wave is defined as three straight days or more of temperatures at or above 90 degrees.

“With these abnormally warm conditions, people really need to drink plenty of water, use air conditioning and do strenuous activities early in the morning or late at night, when it’s not as warm,” Pollina said.

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News 12 Long Island meteorologist Nicole Mitchell said Long Islanders are experiencing an “excessive heat that spreads all the way to the Midwest.”

The normal temperature for this time of year in western Nassau is 84 degrees and 82 in Islip, according to Nelson Vaz, also a meteorologist for the National Weather Service in Upton.

On Monday evening a cold front moves in so Tuesday should bring drier air, Vaz said. Tuesday’s high will be 91 and the low 72. The hazy, hot and humid day will start with morning clouds that will give way to more sun.

The heat wave is expected to end on Wednesday when there will be mostly sunny skies, but the high is forecast to hit only 88 degrees and the low will be 71.

“It looks like Wednesday is the day that we might fall short of the heat wave temperatures,” Vaz said. “On Wednesday, there’ll be gradual cooling.”

Rain is possible again on Thursday when there is a chance of a thunderstorm and the high will reach 87 and the low will be near 70.

Friday will be partly sunny with a high of 85 and a low of 70.