Definition
The final stage in the life cycle of a thunderstorm, characterized by predominantly downdrafts throughout the cell as the supply of warm, moist updraft air is cut off. Precipitation weakens, the cloud begins to lose its vertical structure, and the storm collapses as it can no longer sustain itself.
Plain English
The last phase of a thunderstorm, when it is running out of the rising warm air that fed it. The storm weakens, rain tapers off, and the cloud falls apart.
Context Anchor
Seen in weather training, thunderstorm discussions, and preflight weather decision-making.
Derivation
Dissipate comes from the Latin dissipare, meaning to scatter or break apart. The thunderstorm is literally scattering its energy and structure, no longer holding together as an organized cell.
Why Pilots Care
Pilots must recognize this stage because the storm can still produce turbulence, strong winds, or lightning while it weakens.
Grounding Statement
Picture a thunderstorm cell with rain still falling but no new updrafts feeding it. The cloud loses its sharp top, spreads out, and gradually fades as it runs out of fuel.
Intuition Check
Do not read “dissipating” as “gone.” It means the storm is weakening, not that its hazards have ended.
Example Sentence 1
By the time we crossed the ridge, the cell had reached the dissipating stage and the rain had eased to a light shower.
Example Sentence 2
Even in the dissipating stage, the pilot avoided the area because lightning was still possible.