Are you shooting at the Milwaukee stations out of the end of a gable or through the snow covered roof?
If it is the latter, is possible that your digital signal prior to the snow accumilation on the roof was just above the digital cliff and in the day time it drops some, but it was still strong enough.
Your signals are 2 edge.
Now with the snow cover it may be right on the line of reception/no reception.
Splitting the signal to 3 TVs usually gives 1 a -3.5 dB signal and the other 2 about -7dB depending on the splitter, the roof can add up to -13dB or more.
Add the snow and who knows. I presume this did not happen last winter?
First exercise all your connections to clean off any corrosion that may have accumilated.