I believe that there a few cannons knocking about Pamps, but not as many as in Bansko or Boro for example. It needs to be cold for them to be working, but the snow at the moment is good, so sure you'll be fine. Benson's your man for snow forcasts, he just know's when its going to snow. If you google snow forecast bulgaria, sure that will take you to somewhere close to what you want.
Pamporovo does have a number of snow cannon....BUT........ they 're not working this season. There was a dispute (about money, I believe) and the lake which would normally supply the cannon has been drained, so the pamps cannon are inoperative