These are thin grooves sometimes cut into pavement to help channel water away & provide better traction. While that may be great for cars & other 4 wheeled vehicles, it is not necessarily great for motorcycles.

Car & truck tires are flat on the bottom ; motorcycles are rounded. This means that the rain grooves tend to "grab" at your tires a little bit as you ride. For many, this is more of a psychological issue than a physical one.

It can be a little disconcerting, but it’s not really a hazard. The main things to remember are simply to avoid making any sudden steering inputs & lighten your grip slightly. That is if you feel the front wheel wiggle a tiny bit, go with the flow. Do not overreact by tightening your grip & trying to counter the wiggle. Let your hands & arms absorb the vibration, keep looking straight ahead ( not down ), & you will be fine.