The MWIS weather forecast for Saturday is looking pretty good:

How windy? -> East or northeasterly, 20 to locally 30 with gusts 40mph near major north to south ridges

Effect of wind? -> Mostly small, but significant buffeting in places, not necessarily higher areas

How wet? -> Showers. A few bursts of showery rain, mainly morning

Cloud on hills? -> Clearing. Cloud widespread on higher areas in morning, base 350 to 600m, but will gradually lift, with cloud only rarely on higher summits after midday

Chance of cloud free summits? -> 70%

Sunshine and air clarity? -> Bursts of sunshine, mainly western hills. Haze gradually lifting as the air becoming increasingly clear

Temperature at 600m? -> 2 rising to 4C

And in the valleys? -> Will reach 9 or 10C in the afternoon

http://www.mwis.org.uk/wpfyvm/PD.PDF