Sounds like you need to hang on and see if DL provides a weather waiver, otherwise you will either need to go and play in the rain or reschedule to another time. And yes you will need to pay the fee if they do not issue a waiver.

My guess is that DL will issue a weather waiver if the storm is really going to hit. But there is no telling the dates of the waiver at this time.

Another option is to call and see what they say.