Here is something that I read years ago, & wasn't sure if it was for real-(till I saw it)-your idea(s)?

Question

Supposedly, the sky gets a greenish tint to it right before a tornado hits. This is in the big tornado states such as Kansas
and Texas. It doesn't happen every single time, though. What
causes that? A temperature inversion? Static electricity? Eagerly awaiting your answer...

Answer 1

Clouds often take on a greenish hue before severe storms, but this is most often associated with hail. Hail is usually part of a tornado-bearing storm. Another thought is that these very tall, dense storms are most likely not letting in any sunlight, so the greenish tint may be a reflection of Earth's green foliage, although this theory has been tested to be rather unlikely. Some other studies have determined that the most likely cause of the "green clouds" is in fact the clouds themselves, filtering out certain other wavelengths of the light spectrum. There are ongoing studies on this.

Answer 2

Good question and good answer above. I'd heard about the light scattering theory so did some digging on the internet. This is what I came up with...

No one knows exactly, but here's one idea...

Sunlight is comprised of many different colors. The colors that comprise sunlight get absorbed, reflected and scattered as they encounter the particles in our atmosphere (like Nitrogen, Oxygen, dust, etc...)

For example, our sky is blue because the blue color in sunlight is scattered by particles in our air. When this blue color scatters in all directions, it may eventually hit your eyes, and voila! You see a blue sky.

This type of optical phenomenon is suspected to be the reasoning behind the green sky effect. Exactly why the green hue appears is not exactly known, but the tremendous amount of water vapor may be the culprit.

It is hypothesized that the water vapor makes the clouds look blue. But when the sun is at a low angle, like at sunset or sunrise, the blue is scattered out of light. This may allow the color green to show up more vividly.

Answer 3

I have heard sky turn to a green hue
when there is possibility of tornado
In Saskatchewan there have been tornado touch downs
strong winds,
severe lightning
large size hail.

Answer 4

It's called Tornado Alley that is a region where conditions favorable tornado development.