This episode of Nova  where they, for reasons unknown, rename wet downbursts "rain bombs" is a mis-mash. They attempt to take things weather science has known for 50 years (discovered by the late Dr. Ted Fujita) and make them new discoveries. The producers also imply we cannot forecast them. None of that is true.  And, as you would expect, they try to tie downbursts to global warming -- in spite of a lack of evidence.  They do have some terrific video of downbursts. The one right after Dr. Marshall Shepherd's first appearance (above) is great. If you watch, notice the curl at the lower left side of the screen as the downburst spreads out. That is the fingerprint of a downburst.  © 1978 Michael R Smith The problem is that this science, including the curl, has been known since 1978 -- there's nothing new about it. It is found in Fujita's book on downbursts.  It feels like the producers ran out of ideas and Rain Bombs  is the result. I wish it had been better....