Hi,
If you're unaware of this webcam: http: //ingleboroughwebcam. co.uk/latest-hd-image (remove spaces for it to work - not allowed to post links - sssh)
Great to get a feel of the actual conditions.
I wouldn't worry too much about snow. Not been enough recently. It's the black ice you need to worry about.
When I did it last, in December (similar looking conditions), there was quite a lot of it around. Do you have microspikes? I'd definitely say they're a must this time of the year.
Cheers,
Hugh
P.S. I'll be doing them tomorrow - might see you there! I'll be starting from Ribbleshead