Waldameer is open Saturday May 16th and Sunday May 17th, 12pm-8pm. Water World will not be open those days.
Splash Lagoon is open Friday May 15th 12pm-9pm, Saturday May 16th 11am-9pm, and Sunday May 17th, 11am-8pm. There are several hotels near the resort for ease if necessary!
Open 24 hours, baby! On their Local Hotels page, there are several hotels nearby to choose from. Have fun!