A SPECI Weather criterion includes which atmospheric event?

• A. Thunderstorms (Ts) etc.
• B. Fog clearing rapidly
• C. Drizzle light rain
• D. Snow flurries

Answer: (A)

SPECI is issued when there is a significant change in weather conditions that could affect flight safety, requiring urgent dissemination beyond routine observations. Thunderstorms are a major hazard for aviation—they bring lightning, gust fronts, heavy rain or hail, and potential wind shear—which can dramatically impact aircraft performance and safety, so they clearly meet the threshold for a SPECI. The other options describe weather that is either routine or less impactful in itself (drizzle, light snow) or a change that may not always trigger an urgent report (fog clearing rapidly). The “etc.” in the criterion signals that other severe phenomena, like strong winds or hail associated with convection, would also qualify. Therefore, the atmospheric event included under SPECI criteria is thunderstorms.