Firstly for the north west i don't think this will be an 'event' really at all. The further south and west you are the higher the chance of precipitation, and assuming dew points are below 0c it will fall as snow, I'm not sure but from what I know that snow will not settle if the ground is above 0c, which it will likely be until a large amount of snow has cooled the ground. The best outcome would be the snow to start falling after dark, and have any water covering partially melted snow evaporated by then.