Had weather vaned a minor brainstorm

What does it mean when someone “had weather vaned a minor brainstorm”?

Hi Cooliegirly

Whoever wrote the sentence was playing with words and expressions (purposely mixing them up):
weather a storm

Without any further context it’s impossible to say with certainty what the writer was trying to convey.
Maybe that someone had ‘suffered and survived (“weathered”) a minor disturbence of the mind (“brainstorm”) and now knows which is the right direction (“weathervane”)’.

Just a guess…