[ADTech]

Most likely, the difference in the wet vs dry reception was due to the soupy atmosphere and the wet terrain peaks out in front of you. The wet air will attenuated signals and reduce your fade margin and the wet terrain will slightly change how the signals diffract. Since your reception is barely holding onto the edge of the digital cliff by a few fingernails, it doesn't take very much change in propagation conditions to drop you off the edge.

Your channel 9 issue is with the other antenna. Either you'll have to search for and find a bit better spot for it or you're getting some kind of localized electrical/electronic interference that's masking its signal. A spectrum analyzer is the only effective tool for investigating that possibility.