Which type of advisory is issued for all thunderstorms in the contiguous United States?

The answer is correct because a WST, or Convective SIGMET (Significant Meteorological Information), is specifically issued to alert pilots and air traffic controllers to the occurrence of thunderstorms and severe weather conditions in the contiguous United States. This advisory is essential as it provides critical information about significant convective weather phenomena, such as thunderstorms that can produce extreme turbulence, hail, and significant wind shear—all of which are vital for maintaining aviation safety.

While other options serve important roles in aviation weather reporting, they do not specifically address all thunderstorms in the same way that a Convective SIGMET does. For instance, a CWA (Current Weather Advisory) provides information on weather conditions but is not solely focused on convective activity. An AIRMET (Airmen's Meteorological Information) covers less severe weather conditions and is used for non-convective weather phenomena. TAFs (Terminal Aerodrome Forecasts) provide forecasts for airports, including weather elements relevant to flight operations but do not issue alerts specifically for thunderstorms. Thus, the Convective SIGMET is the appropriate advisory to recognize and communicate the hazards posed by thunderstorms effectively.