Long Island weather: Heat index near 100 Tuesday, Wednesday

Parts of Long Island will be under a heat advisory Tuesday as the region will reach heat index values in the low 100s and see humid conditions through Wednesday.

The National Weather Service said that, except for portions of eastern Long Island, Nassau and northwestern Suffolk County will be under the advisory beginning Tuesday at noon to 9 p.m. on Wednesday.

Meteorologist Nelson Vaz said Monday will see highs in the mid-80s but Tuesday will feel significantly hotter due to increased humidity.

"We are looking at some heat that's been going on in the central U.S. and the western United States that is going to be building into our area for a couple of days," Vaz said.

Tuesday will reach heat index values in the mid to upper 90s. Eastern Long Island will feel cooler compared to advisory areas due to the trajectory of winds off the water, Vaz said.

"Once you get away from those south coastal areas tomorrow, we'll be around 90 degrees, and with the added humidity, it's going to make it feel like it's somewhere in the mid '90s," he said.

Wednesday will be the hottest day of the week with heat index values as high as 105 degrees as the service predicts a decrease in winds.

Forecasters encourage everyone to take precautions in the hot and humid conditions, such as keeping hydrated, staying inside air-conditioned spaces and limiting strenuous activity outside.

"Those are all important things to do, especially in the peak of the heat during the day," Vaz said.

Thursday and Friday see temperatures in the upper 80s to lower 90s, or more typical summer weather, but will feel significantly cooler due to a break in the humidity, Vaz said.

"Nothing that's too unusual," Vaz said.