I too only recieve WGRZ when the weather is on the warmer side and the jetstream. is from a southerly direction however as I stated before i'm on the fringe. ironically next to CBC HD my next strongest station is WIVB. It seems to correspond with weather patterns the jet stream is more likely to arc above spring and summer and by fall and winter it tends to ride below us. sixty miles appears to be the maximum distance a signal can travel reliably in multiple weather conditions.. apparently after this distance the earth's curvature seemingly distorts (intereferes) with signals.