WZTK suffering from tropospheric ducting

Watch out for that tropospheric ducting, according to WZTK (101.1FM)...the natural phenomenon is making the station's incredibly strong signal weak in some parts of the greater listening area, according to station officials.

And what is tropospheric ducting?

Tropospheric ducting is a type of radio propagation where instead of radio waves reflecting off the ionosphere and back down again like as for a skywave, tropospheric ducting is where radio waves are reflected up and down in a duct formed by humidity and moist air, acting very much like an optical fibre. The ducting is most common at microwave and UHF frequencies, working its way down into the VHF range in pronounced cases. Tropospheric ducting often results in reception of television and FM broadcast stations hundreds of miles distant.

So there...

E.C. :)