A couple weeks ago when we were getting our last deluge of rain I noticed my Ranger started doing a strange, high frequency vibration. It only does it when it's wet outside, or actively raining. It's been dry for almost 2 weeks, and I forgot about it until today's rain. 

If I'm doing 15-20 mph or so and lightly braking while turning, like turning in a parking lot or going through a curve, a loud vibration will happen and you can feel it in the floor. As far as I've noticed, it only happens on a right turn, not a left turn, and it must be wet or raining, otherwise it won't happen. It's also not an every time thing. I suspected CV axles in the front end, but the boots are good. They're also not locked in, which I would say rules them out. The sound/ feeling is almost like dragging a table or something on a hard floor.