What is Virga and how does it work

In previous letters, we talked about where rainfall and drizzle come from. In this new lesson of the Windy.app Meteorological Textbook (WMT) and newsletter for better weather forecasting you will learn more about Virga and how it works.

Surely, you have observed how sometimes streaks «hang» from under the clouds — this is a so-called virga, which can appear under cumulonimbus clouds.

This is the same rain, but it evaporates before reaching the surface of the earth. The reason for this is low ambient humidity. That is, dry air in the way of drops tends to saturate with moisture and "absorbs" them.

So the rain simply evaporates on the way to the earth. Due to the evaporation, the surrounding air becomes colder — a cold air mass goes down and suppresses new air flows rising under the cloud. This becomes the main reason for the cessation of the growth of the cumulonimbus cloud, and it is destroyed.

Text: Windy.app team

Cover photo: Unsplash