Which of the following conditions would trigger Aviation severe weather watch bulletins?

Aviation severe weather watch bulletins are specifically designed to alert pilots and airline operations about conditions that can significantly impact aviation safety. The presence of funnel clouds or tornadoes is a critical condition that warrants such alerts, as these phenomena can cause severe turbulence, dangerous wind shear, and other hazardous scenarios for aircraft both in flight and during takeoff or landing. Tornadoes, in particular, pose an extreme threat due to their intensity and unpredictability, making timely warnings essential to mitigate risks to aviation operations.

In contrast, while low visibility, sustained winds of 30 knots, or heavy rain can certainly affect aviation, they do not inherently trigger severity alerts in the same way that tornadoes do. Low visibility might lead to operational adjustments, but it is not classified as severe weather. Sustained winds of 30 knots can be considered significant, yet they may not reach the threshold for a severe weather warning without other contributing factors. Heavy rain, while it can reduce visibility and create some hazardous conditions, is typically not classified as severe weather on its own unless it leads to hazards like flooding or low-level wind shear.