Here's the hourly prediction for Saturday morning from Accuweather: Gaithersburg. Apparently, as of now, they're predicting the rain will be over by 1 in the afternoon.

Regina, I got your e-mail and at this point, I'm definitely saying no to a morning ride. Do you (or anyone else) want to ride in the afternoon, or will there be too much traffic on the roads by then? If this road ride doesn't happen, I'll probably head out to Hancock and ride the Western Maryland Rail-Trail in the afternoon. I haven't been on the bike since my GAPt ride last Thursday, and withdrawal is setting in!