9 a.m. Update: The weather service had dropped the chance of showers and thunderstorms during the day Sunday to 30 percent.
However, there's now an 80 percent chance of precipitation Sunday evening, and some of those storms could be severe, the service says.
Previous story: The National Weather Service is predicting a possibility of severe thunderstorms Sunday in York County, with storms most likely after 2 p.m,.
The storms could be accompanied by large hail and damaging winds, the weather service says.
The chance of precipitation during the day on Sunday is 60 percent. That chance jumps to 70 percent Sunday night, when showers and storms are most likely before 2 a.m.
Sunday's high will be 85 degrees.
Monday's forecast calls for a 40 percent chance of rain and scattered thunderstorms, with a high of 82 degrees.
Cooler weather will follow. Temperatures aren't expected to hit 80 degrees on Tuesday or Wednesday when the forecast calls for sunny skies and no precipitation.