Am amazed how many people post wondering about the weather! We all know its gonna snow, thats why Bulgaria is a ski destination! Yup, if you go very early, or very late in season the conditions might not be fantastic - just like a summer holiday in fact!!
If ya need any more convincing that weather changes on a daily basis - check the web-cams on this site, look at Dec 7, then Dec 8! See, no worries!
I had access to the 6 day forecast for a bit and it all looks good (if you go by snow forecasts). Although how many cm's of snow might not be accurate, there seems to be a trend for more and more snow and colder temps over the weekend wit some big dumps on friday and monday.