Just for reference, here is a link to a site that has tropospheric ducting maps that show where and when you could get interference.This one primarily covers the eastern half of the US from roughly the Dakota’s/Texas to the Atlantic. The time on the maps is UTC, so subtract 5 hours (eastern) or 6 hours (Central). Strong ducting often means that signals from further away can interfere with your local signals. In the analog days, this would cause double-images or ghosting. With digital, it causes noise that can sometimes prevent reception.
I note this as the Chicago/Michigan/Wisconsin area is having and in for strong ducting through Wednesday. Horrible timing as WBBM is shutting down the RF12 signal as that will be used as the ATSC 3.0 lighthouse. WBBM already has their “new” signals live across 4 stations. I don’t want to touch my Tablo until I have usable signals, at least for the stations I normally have in it’s guide. Right now, I have lost WTTW (PBS) and WFLD (Fox) due to interference.