What are SIGMETs and Convective SIGMETs and how should they influence routing decisions?

• A. They indicate routine weather with no routing impact
• B. They only apply at high altitude
• C. They are optional advisories
• D. They warn of significant weather hazards including severe convective activity; route around storms or delay operations.

Answer: (D)

SIGMETs and Convective SIGMETs are warnings about significant weather hazards that can affect flight safety and routing decisions. They indicate conditions that may pose serious risks to aircraft performance or safety, such as severe icing or turbulence (non-convective SIGMETs) and active convective weather like thunderstorms with damaging winds, large hail, or tornadoes (Convective SIGMETs). Because these hazards can develop quickly and cover wide areas, pilots and flight planners use them to shape routing by avoiding affected airspace or delaying operations until the weather hazard diminishes. They’re not routine or optional advisories; they are safety notices that require consideration in planning and en route decisions.