Define Raining Mightymen And Mutherfuckers Meaning

Raining Mightymen And Mutherfuckers
A very Heavy Rainstorm with high winds but not classified as severe.

As Harry came in soaked from the storm he replied "Damn, It's raining Mightymen and Mutherfuckers out there!"
Raining Cats and Dogs
By Sydelle