In reply to g taylor: Seriously, if winds are up to 60 mph, you will experience gusts up to 80 mph, I would not be on grib goch in those winds, sorry but you will get blown around.
What was the weather forecast you have seen? Friday looked OK last time I checked. If gusts are to 60 then you may 'just' get through. Even then, rather you than me.
I was up on Glyder Fach/Fawr last week and even in 40-50 mph winds, with gusts getting over 60 mph, it was dificult on the wet boulders.
I'm planning on running over the Elidirs tonight as the winds shouldn't be too bad, on thursday I had organised a run up snowdon but they may be called off due to high winds, but then at 5 am on Friday I'm due to run up Elidir to support someone and the weather at the moment looks suprisingly kind.
Good luck, but we've had some big winds in the past few weeks.