If your stormy scenes feature the same few words over and over again, this list can help you get more specific with your rain descriptions. Don't worry, I'm not just going to say "rainy" and "wet".
Cascading
Rain pouring down in a continuous waterfall-like cascade
Beads
Beads of rain might cling to clothes/hair like jewels (or...beads)
Lashing
Rain that falls in heavy, forceful bursts
Pelting
Rain that falls in large drops hitting surfaces with force
Drumming
Rain that falls heavily and rapidly, creating a rhythmic sound. It beats on windows, etc.
Churning
Rain that seems to be in constant, chaotic motion
Frenzied
Intense, chaotic rainfall
Roaring
Loud rain (the sound may come from wind)
Howling
Similarly, it’s rain driven by fierce winds, making a howling sound
Rumbling
Rain that makes a deep, rumbling sound, usually from thunder
Pattering
Rain that falls with a pattering sound, often on windows, tents, etc.
Drizzle
Fine, wispy drops
Sheets of rain
Rain falling in a wide curtain
Walls
Rain falling so heavily it appears as a solid wall
Streaking
Running down windows in rivulets
Murky
When rain makes the air thick and unclear.
Dimpling
When rain hits a body of water and leaves little dimples in it
Slanting
When wind blows the rain at an angle
