York won't get a break from the heat and humidity on Thursday, but the weather should be more bearable by the weekend.

All of south central Pennsylvania is under a heat advisory until 8 p.m. Thursday, according to the National Weather Service. Temperatures are supposed to reach the mid-90s in the afternoon, with a high of 97 predicted for York, and the heat index will be 100-102.

The Susquehanna Valley is also under a code orange air quality alert Thursday, according to the state Department of Environmental Protection. That means air pollution concentrations could be unhealthy for sensitive groups, including children and the elderly and people with asthma or heart disease.

Everyone is advised to avoid strenuous activity outside, and to take frequent breaks in an air-conditioned space or in the shade. People are also reminded not to leave children or pets alone in a vehicle, where temperatures can become lethal within minutes.

York has a slight chance of showers or thunderstorms Thursday evening, and the low will be 72, the weather service said.

Friday will be mostly sunny, with a high of 90, and showers and thunderstorms are likely in the evening, the forecast said. Friday night's low will be 65.

Saturday will be mostly sunny, with a high of 86 and low of 60, the forecast said, and Sunday will be much the same, sunny with a high of 85 and low of 64.

Monday has a chance of showers and thunderstorms, along with a high of 80 and low of 60, the NWS said.