Long Island forecast: A hot, muggy Thursday with heat index near 100

Another round of hot, muggy weather is in the Thursday Long Island forecast after Wednesday's version led to a heat advisory and an estimated heat index that hit the upper 90s

The advisory was set to end at 10 p.m. Thursday. Like Wednesday, the high Thursday will top out about 88 degrees. The heat index is forecast to approach 100 degrees, according to the National Weather Service.

A 30% chance of thunderstorms Wednesday night will climb to 40% after 5 p. m. Thursday. Otherwise, Thursday will be partly cloudy with an overnight low of 72.

The state Department of Environmental Conservation issued an air quality advisory Wednesday through 11 p.m. Wednesday for because of high ozone levels.

The advisory includes the New York City Metro and the Lower Hudson Valley.

Ozone, a major component of smog, forms from a chemical reaction related to auto exhaust and industrial emissions, the state DEC said.

People, especially those with cardiovascular or respiratory diseases, young children and the elderly, or those who exercise or work outdoors, should consider limiting strenuous outdoor activity, according to state officials.

Forecasters encouraged all to use air conditioning to stay cool at home or go to a place that has air conditioning, especially seniors, young children and those with chronic health problems.