Definition
A strong downward flow of air created when falling precipitation drags surrounding air with it and cools that air through evaporation, causing it to become denser and accelerate toward the ground. Often associated with thunderstorms and the formation of microbursts and wind shear at low altitudes.
Plain English
A column of air pushed downward by falling rain. The rain pulls air down with it, and as some of the rain evaporates it cools the air, making it heavier and faster. The result is a powerful rush of air heading toward the ground.
Context Anchor
Encountered in weather discussions about showers, thunderstorms, approach and departure conditions, and sudden sinking air near heavy precipitation.
Derivation
Precipitation comes from the Latin praecipitare, meaning to throw down or cast headlong. Downdraft is a plain compound: a draft (current of air) moving downward. Together the term describes a downward air current set in motion by falling precipitation.
Why Pilots Care
These downdrafts often create sudden wind shear that can cause rapid loss of altitude, especially dangerous near the ground on approach or departure.
Analogy
It is like a curtain of falling water tugging nearby air down with it. If that air also cools and becomes heavier, it can sink even more strongly.
Grounding Statement
Imagine rain falling through dry air below a thunderstorm. The rain drags air down with it, and as droplets evaporate the air cools and gets heavier, accelerating the whole column toward the surface where it spreads out violently on contact.
Intuition Check
Do not think of precipitation only as a visibility problem. In this term, the important point is that falling rain or ice can create sinking air that affects aircraft control and altitude.
Example Sentence 1
The flight crew diverted around the cell after the briefing warned of strong precipitation-induced downdrafts in the area.
Example Sentence 2
On short final the aircraft encountered a precipitation-induced downdraft that produced a sudden sink rate requiring immediate power addition.