I find that the Norwegian site yr.no can give a pretty accurate forecast hour by hour for our local village and seems to be able to do this for anywhere on the planet ---Try it out! its Free!!!!
Robbie I agree totally - We were encouraged to use this site by Laurens & highlighted by Chris for this years Grindlewald trip and it's really accurate far more so than the BBC.
The Jungfrau region has its own weather system contained within the alps and this site really provided a service to rely on.
Combine this with weather and radar for real time plotting and you can't go wrong.