Which of the following is NOT part of the criteria for Convective SIGMET?

The criterion that is not part of the requirements for Convective SIGMET is that the weather should develop as forecasted. Convective SIGMETs are issued to warn pilots about hazardous conditions due to convective activity, such as thunderstorms. They are based on the observation of severe weather phenomena, including thunderstorms that produce significant turbulence, wind shear, or hail.

The expectation for weather to develop as forecasted is not a criterion because Convective SIGMETs themselves are based on current observations rather than predictions. It is essential to provide timely and accurate information about existing conditions that could pose risks for aviation, rather than confirming adherence to forecasts.

The other criteria are vital for ensuring pilot safety and operational efficiency. Maintaining Visual Meteorological Conditions (VMC) is crucial for pilots flying under visual flight rules, while continuous radar monitoring ensures that real-time updates on storm activity are available. The availability of a suitable divert aids in safety planning should the weather or flying conditions deteriorate. Thus, these elements are integral to the issuance and monitoring of Convective SIGMET, while the development of weather aligns more with forecasting rather than the immediate data-driven nature of the SIGMET criteria.