No doubt, it will be very wet up there, as your right in the heart of the central Brecon Beacons.
The area of the Brecon Beacons near the Gap or Roman Road, retains a lot of moisture, and the weather has been unsettled recently.
Tomorrow, the forecast is supposed to be decent, but from Tuesday night and onwards, the weather is supposed to be getting very unsettled, all the way into next week.