In a nutshell the FCC had an auction where full powered stations could do a few things in return for some money (a lot depending on market size)
-go off the air (sell their station license)
-move from UHF to VHF High (if they were on UHF)
-move from UHF or VHF Hi to VHF Low
or do nothing. This was to chop the upper channel to 36 now (instead of 51).
So the stations that did nothing the FCC has to move RF stations around to "make it fit". So your Full powered stations are all moving to new RF stations in Late 2019. Low powered stations are not protected and there will be a timeframe that they can apply to move to an open frequency.
Now just because a station may have sold their RF station doesnt mean they are leaving the airwaves. Some (most) will do channel sharing with another station (usually one that they already own). Some will channel share with another station in the area. As example where I live (Minneapolis, MN) there is a satellite station of the CBS (WCCO) in the west central part of the market (most of MN is the Minneapolis market according to Nielsen) that CBS sold off for about 10 million dollars. KCCO is an owned and operated station. There is only 3 full powered stations in that part of the state (and one is PBS). Since CBS has said they will channel share the obvious choice is to piggyback on the ABC there (KSAX which is owned by Hubbard Broadcasting).
Its possible Weigel may not be able to keep all 3 of their stations and will channel share (kinda like smaller markets do now where you will have 2 networks on one station.) The only difference is the stations will keep their PSIP