FAA Airline Transport Pilot (ATM)Meteorology and Weather ServicesMedium
A dispatcher reviewing radar data notes that a thunderstorm cell now shows predominantly weakening downdrafts, diminishing rainfall intensity, and a cloud top that has flattened into a spreading anvil shape. Which stage of the thunderstorm life cycle is this cell in?
- ACumulus stage
- BMature stage
- CDeveloping stage
- DDissipating stage
Show answer & explanationAnswer & explanation
Correct answer: D. Dissipating stage
The dissipating stage is characterized by weakening downdrafts throughout the cell, decreasing precipitation, and the anvil-shaped cloud top spreading downwind, as the storm loses its supply of warm, moist updraft air.
Why the other options are wrong
- A. Cumulus stage has only updrafts and no precipitation, the opposite of this scenario.
- B. The mature stage has strong coexisting updrafts and downdrafts, not weakening downdrafts.
- C. 'Developing stage' is not a standard term; the correct early stage name is cumulus.
Thunderstorm Dissipating Stage
The final stage of a thunderstorm's life cycle, dominated by weakening downdrafts as the storm's updraft is cut off, leading to decreasing precipitation and turbulence.
- Downdrafts spread out and cut off the warm moist inflow
- Precipitation and lightning gradually decrease
- Anvil cloud top remains and spreads downwind
Memory trick: Dissipating = the storm runs out of gas as downdrafts choke the updraft