Thunderstorms (AC 00-24C)
Advisory Circular 00-24C provides guidance on thunderstorm hazards and avoidance. It covers the lifecycle of thunderstorms (cumulus, mature, dissipating stages), associated hazards (turbulence, hail, microbursts, lightning, icing), and recommended avoidance procedures for VFR and IFR pilots.
Why This Document Matters
Thunderstorms are among the most dangerous weather phenomena for aviation, and this AC is the FAA guide to understanding and avoiding them. It covers the three stages of thunderstorm development, the hazards each stage presents, and practical guidance for avoidance. The AC is particularly important for instrument pilots who may need to deviate around thunderstorms, but VFR pilots must also understand when convective weather makes flying unsafe. Thunderstorm questions appear on every FAA knowledge test.
Chapter-by-Chapter Guide
What each section covers and the key topics to study
1Thunderstorm Formation and Lifecycle
The three stages of thunderstorm development and conditions required for thunderstorm formation.
Thunderstorm Formation and Lifecycle
The three stages of thunderstorm development and conditions required for thunderstorm formation.
Key Topics
2Thunderstorm Hazards and Avoidance
Specific hazards including microbursts, hail, lightning, and recommended avoidance procedures.
Thunderstorm Hazards and Avoidance
Specific hazards including microbursts, hail, lightning, and recommended avoidance procedures.
Key Topics
Study Tips
- Memorize the three stages: cumulus (updrafts only, building), mature (most dangerous, both updrafts and downdrafts, precipitation begins), dissipating (downdrafts only, rain without lightning).
- Remember the 20 NM rule: avoid thunderstorms by at least 20 nautical miles laterally, especially anvil clouds where hail can be thrown well clear of the visible storm.
- Understand microbursts: a localized column of sinking air that can produce wind shear of 45 knots within 2-4 miles. Microbursts last 5-15 minutes and are the most dangerous near the ground during takeoff and landing.
Frequently Asked Questions
What are the three stages of a thunderstorm?
The three stages are: (1) Cumulus — characterized by updrafts only, building vertically; (2) Mature — the most dangerous stage with both updrafts and downdrafts, precipitation reaching the ground, and maximum turbulence; (3) Dissipating — characterized by downdrafts only, with the storm weakening.
How far should I stay away from a thunderstorm?
The FAA recommends staying at least 20 NM away from thunderstorms, especially severe ones. Hail can be thrown several miles from the storm cell, turbulence can extend well beyond the visible cloud, and gust fronts can spread far ahead of the storm.
Quick Facts
- Document ID
- AC 00-24C
- Last Updated
- 2013
- Cost
- Free
- Publisher
- FAA
Applies To
Study Smarter
Get AI-powered study tools that turn the AC 00-24C into interactive flashcards, practice questions, and personalized study plans.
Try VectoredOps FreeNo credit card required
Master These Documents with AI-Powered Learning
VectoredOps turns FAA handbooks into interactive study tools. AI-generated flashcards, practice oral exams, and spaced repetition help you retain what you read.
Try VectoredOps FreeNo credit card required
Thunderstorms (AC 00-24C) is an official FAA publication available at FAA.gov
VectoredOps is not affiliated with the Federal Aviation Administration. Always verify you have the most current version of any document before use.