You could make the case that mom would have wanted it this way, and mom gets what she wants on Mother's Day. It was a beautiful Sunday with low humidity and comfortable temperatures.
Monday will bring a return to Summer-like heat, and a touch of humidity. The warm airmass may even help to spark a stray thunderstorm late in the day as a warm front lifts north across Central PA. The activity wouldn't be widespread, but we can't rule it out either.
Tuesday offers a slightly better chance for some scattered showers and thunderstorms as the air really gets juicy with highs in the mid to upper 80s.
The period Wednesday through Friday will see a cold front essentially become stationary over the eastern United States. Strong southerly flow will keep the threat of downpours and thunderstorms in the forecast for all three days, potentially with heavy localized rainfall. It is extremely difficult to say how much rain and where it will occur, but we will be monitoring this closely as more details become available.