Sound like they are doing good - sweet huh?
I get about 5 pounds of honey per large super frame, and about 2 pounds per medium super frame. So if you have 10 frames in your mediums, you can estimate about 15-20 pounds per super. That's IF they did a real good job filling all the frames. (And a quart jar holds 3 pounds. So ya better get yourself on out to Wal-Mart and buy a case or two of jars.
But like I said.... you can pretty much guarantee 1 1/5 to 2 pounds per medium frame that's well covered.
I'm in central Georgia, and my bees eat hardly any honey through the winter. But our winters are so short here, and we have flowers blooming year round. Each hive has gone through less than 10 pounds for the whole winter, and the queen starts laying strong by the end of January.