ETYMOLOGY
from Latin imbrifer (from imber (a shower))
EXAMPLE
“…at a time when large mountainous cumulostrati and cumuli appear more stationary, somewhat higher up, and when flimsy features of cirrostratus, cirrocumulus, and cirrus are visible in a region still more elevated. When this Scud is abundant we may be sure the imbriferous quality of the atmosphere remains, and we may expect a return of the showers…”
From: Researches about Atmospheric Phaenomena
By Thomas Forster, 1815
Lexicophilia 