Difference using そう with various verb forms?


I'm doing some reviews on Bunpro and I got this sentence:

> 今晩雨が＿＿＿。

And I knew it wanted the verb 降る, and that it wanted me to use そう.

So I put in ふりそう, and was surprised to see that it actually wanted ふるそう.

I know I've seen the い-ending of verbs with そう as well. What's the difference
in meaning between these two constructions?




I believe this is a difference between two grammar points:

  * 雨が降りそう means "it looks like it's going to rain"
  * 雨が降るそう means "I heard it's going to rain"

See [This grammar guide's
explanation](http://guidetojapanese.org/learn/grammar/similarity#Guessing_at_an_outcome_using):

> Guessing at an outcome using 「～そう」

> Expressing hearsay using 「～そうだ」

For verbs, the first is constructed with the stem, and the second is
constructed by adding the verb as-is.




I believe this is a difference between two grammar points:

  * 雨が降りそう means "it looks like it's going to rain"
  * 雨が降るそう means "I heard it's going to rain"

See [This grammar guide's
explanation](http://guidetojapanese.org/learn/grammar/similarity#Guessing_at_an_outcome_using):

> Guessing at an outcome using 「～そう」

> Expressing hearsay using 「～そうだ」

For verbs, the first is constructed with the stem, and the second is
constructed by adding the verb as-is.

