it is the sound of a tornado! You can verify by taking an old B&W
TV set, tuning to Channel 2, reducing the brightness till the picture
goes away. The lightning will show up as lines of hash. A tornado emits
so much RF that it will turn the screen white, if it is within about 15
miles of the set.

I checked the web but couldn't find the frequency spectrum for
tornados, etc. weather phenomena.

Being the owner of a scanner radio that can receive most any
frequency, I am wondering if there are even better frequencies than
just the TV bands to hear tornados on?

Lightning's frequency spectrum is concentrated where?

Hurricanes listenable? Any other phenomena listen able?