Tenki-Ame (Sunny Rain)

Yesterday, I talked about the etymology of "kitsune-no-yomeiri (rain when the sun is shining)."

This phenomenon is officially expressed as "tenki-ame" or "hideri-ame" in Japan ("tenki" and "hideri" mean "sunny," and "ame" means "rain").

Today, I will explain the scientific occurrence reasons of the tenki-ame.

The conditions are able to be divided into two major cases.

One is that rain clouds dissipate before raindrops reach the ground.

If the clouds are convective clouds, since it tends to dissipate after the rainfall, it's easy to become tenki-ame.

Another one is that rains come from a long distance by strong crosswinds.

This phenomenon is often found in mountainous areas.

Also, since sunlight will hit raindrops during the tenki-ame, you will be easier to find rainbows.

天気雨

昨日は、狐の嫁入り（日が出ているのに降る雨）の語源について説明しました。

この現象は、日本では正式には「天気雨」や「日照雨」のように表現します。

今日は、天気雨が発生する科学的な理由を説明します。

天気雨の発生条件は大きく二つに分けられます。

一つは、雨粒が地面に到達する前に雨雲がいなくなることです。

雲が対流雲であった場合、降雨後消えやすく、天気雨になりやすいです。

もう一つは、遠くで降った雨が強い横風に流されて、雲の無いところに飛んで来ることです。

この天気雨は、山間部でよく見られます。

また、天気雨は日光が雨にあたりやすいことから、虹を観察できる可能性が高くなります。

• Yesterday, I talked about the etymology of "kitsune-no-yomeiri (rain when the sun is shining)."
• This sentence is perfect! No correction needed!

• This phenomenon is officially expressed as "tenki-ame" or "hideri-ame" in Japan ("tenki" and "hideri" mean "sunny," and "ame" means "rain").
• This phenomenon is officially expressed as "tenki-ame" or "hideri-ame" in Japanese ("tenki" and "hideri" mean "sunny," and "ame" means "rain").

• Today, I will explain the scientific occurrence reasons of the tenki-ame.
• Today, I will make use of what we understand in meteorology to explain tenki-ame.

  meteorology = study of atmosphere / weather
  
  I think this is what you mean, but I could be a little off.

• The conditions are able to be divided into two major cases.
• The weather conditions can be divided into two categories.

  Clearer

• One is that rain clouds dissipate before raindrops reach the ground.
• In the first category, rain clouds dissipate before raindrops reach the ground.

  If you would like to signal to the reader in a clearer way, else you can just assume the reader knows you are referring to the first category.

• If the clouds are convective clouds, since it tends to dissipate after the rainfall, it's easy to become tenki-ame.
• However, if the clouds are convective, they dissipate after rainfall, resulting in tenki-ame.

  Rainfall isn't distinctively unique so 'the' is replaced with 'a'.
  
  I am trying to connect your previous sentence so that the meaning is clear. I am not sure if I got it right.

• Another one is that rains come from a long distance by strong crosswinds.
• Finally, we have rain that arrives from a great distance through strong crosswinds

  Your final category.

• This phenomenon is often found in mountainous areas.
• This sentence is perfect! No correction needed!

• Also, since sunlight will hit raindrops during the tenki-ame, you will be easier to find rainbows.
• Also, since both the sun and rain are present during tenki-ame, rainbows are a common sight.

  I prefer writing it this way.

Unfortunately, I am not sufficiently caught up in meteorology but it's clearly your interest.

• This phenomenon is officially expressed as "tenki-ame" or "hideri-ame" in Japan ("tenki" and "hideri" mean "sunny," and "ame" means "rain").
• This phenomenon is officially expressed (or: commonly known) as "tenki-ame" or "hideri-ame" in Japanese ("tenki" and "hideri" mean "sunny," and "ame" means "rain").

• Today, I will explain the scientific occurrence reasons of the tenki-ame.
• Today, I will explain the science behind the tenki-ame.

Interesting! I think there was a song called "Sunrain", but I don't remember who it's by.^_^