There are 2 types of a wet/dry condition. One is a side to side wet/dry, the other is a front to back wet/dry.
So here's what happens when you're bowling on a side to side wet/dry. Let's say you are lined up or maybe you're not even lined up, but what happens is when you miss your mark to the inside, the ball doesn't hook and misses the headpin or leaves a bucket.
Now, when you swing the ball to the right, it hits the dry and goes to the beek or even brooklyn. That's called over/under on a wet/dry condition.
On a front to back wet/dry, the ball will hook violently on the backend as soon as the ball comes off the oil pattern down the lane. The oil is usually flatter, with no hold in the middle, because the backends are stripped squeeky clean. So, no matter how deep you get, the ball will hook to the nose or brooklyn if you keep the ball tighter inside.
Now, when you swing the ball out farther to compensate for all the hook on the backend, the ball doesn't make it all the way back, usually leaving you a washout. That's the kind of over/under you get on a front to back wet/dry condition. The PBA is famous for this condition. =:^D
