Intermittent reception problems?

[audiopile]

Is this just a bad night for HD? Several channels that I normally get perfectlly are now unwatchable ( 36-1 (35),18-1 (61) and 12-1 (34) are all showing a flickering signal strength with the resulting flickering,pixelation and black screen. 36-1 in particular has never been anything but rock solid in the past.
     Did the pigieons re-align themselves on the water tower or what?