A heat advisory is in effect for York County through Tuesday evening, according to the National Weather Service.
Temperatures in the region are forecast to climb as high as 98 degrees, but humidity will push the heat index to about 100 degrees. Clouds are expected to roll in this afternoon for a warm night, with a low around 74.
The weather service also has issued a "code orange" air quality alert for the Susquehanna Valley through Tuesday. A code orange means people in sensitive groups - those suffering from heart disease, as well as asthma and other lung conditions - should avoid strenuous activity or exercise outdoors.
Wednesday will be mostly sunny, with a high near 95 degrees, and brings a 50 percent chance of afternoon showers and thunderstorms, but the precipitation is unlikely to offset York County's drier-than-normal conditions. New rainfall will amount to less than a tenth of an inch, though thunderstorms could bring more, according to the weather service.
Temperatures are forecast to drop slightly through the rest of the week, and light precipitation is likely to persist until Friday. The early forecast for the weekend is pleasant, with mostly sunny skies and a high of 84 degrees Saturday.