Definition
To break up, scatter, or thin out until something is no longer concentrated or no longer present. In aviation contexts, dissipate is most often used to describe weather phenomena (fog, clouds, thunderstorms, turbulence) losing their structure and fading away, or energy (heat, static electricity, wake turbulence) being spread out and absorbed by the surrounding environment.
Plain English
To gradually break apart and disappear, or to spread something out until it fades away.
Context Anchor
Seen in weather discussions, turbulence reports, aircraft systems descriptions, and explanations of how hazards weaken over time.
Derivation
From the Latin dissipare, meaning to scatter or throw apart (dis- = apart, supare = to throw). Knowing it literally means scatter apart helps fix the idea: a dissipating fog isn't being destroyed, it's being broken up and spread thin until you can no longer see it as fog.
Why Pilots Care
Forecasts often hinge on when something is expected to dissipate. Knowing fog will dissipate by 1000 local can decide whether you depart on time or wait. Knowing a thunderstorm has not yet dissipated keeps you clear of it even if it looks weaker on radar.
Grounding Statement
Picture morning fog slowly thinning until the runway becomes clearly visible.
Intuition Check
Dissipate does not always mean vanish instantly. In aviation, it usually means a condition is spreading out or weakening until it no longer has an important effect.
Example Sentence 1
The morning fog is forecast to dissipate by 0900, so we delayed the departure by an hour.
Example Sentence 2
The isolated thunderstorm continued to dissipate as it moved over cooler air.