Re: Why not use 4G/5G?
As far as I understand, this has not been explained correctly in the article. Weather satellites detect the presence of water vapour (and other atmospheric gases) by firing microwave signals downwards and detecting what comes back up. Water vapour absorbs radiation at around the frequency of the proposed 5G frequencies (I believe), which is why ground based emissions at the same frequency will completely screw these observations (obviously the signal power reflected back to the satellite is tiny, so the 5G signal would swamp any observation).
Satellite observation is by many orders of magnitude the most useful input to a weather forecast, and removing this observation type, would have a significant decremental effect on the accuracy of the forecast.