Okay, took another look at weather.com and they're now calling for 40% chance of scattered thunderstorms at 19.00 and 45% at 20.00 and 21.00; however, after that it goes back up into the 50-60 percent range; also calling for 75% chance of thunderstorms at 18.00.
I think it's the lightning, as much as (if not more than) the rain, that is the real threat to getting our opener into the books.