hy·dro·me·te·or·ol·o·gy 
(hī′drō-mē′tē-ə-rŏlə-jē)
(hī′drō-mē′tē-ə-rŏlə-jē)n.
The branch of meteorology that deals with the occurrence, motion, and changes of state of atmospheric water.
hy′dro·me′te·or′o·logi·cal (-ôr′ə-lŏjĭ-kəl, -ŏr′-) adj.
hy′dro·me′te·or·olo·gist n.