Dancing in the rain, underneath the sunny skies?

[mbarker]

The news people get various questions, and often answer them. But the weather reporters rarely get questions. However, this morning, they had a question from a viewer! The question was simple: why do we sometimes have rainfall in the sun?

Time out for a short Japanese lesson: 狐の嫁入り　（きつねのよめいり） Foxes' wedding -- idiomatic phrase for showers with the sun shining, aka sunshower. Apparently based on a folk tale of a wedding of foxes during such conditions. I wonder if it is also a comment on the rarity of such events?

And why do we have sunshowers?

The weather person -- a young woman, in this case -- explained that there are two major reasons. First, while the rain may fall from a cloud over there, sometimes there is enough wind to make the drops fall over here... out from under the cloud, in the sun. So you might say the wind is teasing us with borrowed raindrops?

Second, apparently rain takes a while to fall -- she said the average time from cloud to ground is ten seconds -- and while the drops are falling, the cloud may get blown out of the way, so that when the drops get to the ground, the sun is shining. Again, the wind is at fault, but this time it just moved the cloud out of the way and let the sunshine in.

Those were all the answers she gave. I have to admit, I had a momentary impulse to try to figure out the terminal speed of falling raindrops, the average height of clouds, and then see if that ten seconds really made sense -- then I decided it was close enough. And I briefly pondered other mechanisms... e.g., I know that hailstones sometimes get bounced up and down for a while, building up size, before finally being dropped. Might rain get stuck in that kind of aerial dance, dropping on our heads when we least expect it, out of a sunny sky? Or perhaps the nanotech ships of the invaders are grabbing raindrops and attacking?

Or... what other reasons could there be? Invisible clouds? After all, how much water vapor does it take to make a cloud visible, and how much does it take for condensation? Can you wring raindrops out of a "clear" sky?

Something to ponder!

Comments

[masgramondou.livejournal.com]

Angle of sun. If it's a significant time before/after noon then the sun could be many (say 45+) degrees from vertical. That means the cloud has to be quite large to cover the sun too

[mbarker.livejournal.com]

Oh, you're right! In fact, rain tends to fall vertical, except when driven by the wind, while sunshine most often is slanted. Good point!