Wednesday was upgraded to an Alert Day in south-central Pennsylvania, with the strongest thunderstorms expected between 7 p.m. and 4 a.m. and a chance of life-threatening weather.
A level 2 of 5 severe risk covers the entire Susquehanna Valley, with damaging winds and flash flooding the main threats; large hail and a brief spin-up tornado are lower risks.
Thursday remains an Impact Day, with scattered storms possible from morning through evening and the highest chance between 10 a.m. and 9 p.m. as a cold front approaches.
A heat advisory runs from 11 a.m. to 8 p.m. Thursday across all of south-central Pennsylvania, with temperatures in the 90s and heat index values near 100.
Conditions improve after Friday, with lower humidity arriving Saturday and more comfortable weather expected through Sunday and Labor Day.