Which one of the following is NOT a favourable condition for occurrence of a thunderstorm ?

Thunderstorm formation requires three primary ingredients: moisture, instability, and a lifting mechanism [3]. Favorable conditions include an adequate supply of moisture in the lower atmosphere to provide latent heat energy [3]. Atmospheric instability, specifically conditional and convective instability, is essential as it allows air parcels to rise buoyantly [4]. Furthermore, a synoptic environment featuring low-level convergence and upper-level divergence facilitates the necessary vertical motion and deep convection [2]. Option 3 is incorrect because it describes the advection of cold dry air in the lower troposphere and warm moist air in the upper troposphere. In reality, convective instability is triggered by the advection of warm, moist air in the lower levels (increasing buoyancy) and cold, dry air in the middle or upper levels (increasing the lapse rate), which creates the potential for violent updrafts [4].

Sources

1. [3] https://www.weather.gov/source/zhu/ZHU_Training_Page/thunderstorm_stuff/Thunderstorms/thunderstorms.htm
2. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > thunderstorms > p. 51
3. [4] https://repository.library.noaa.gov/view/noaa/7058/noaa_7058_DS1.pdf?
4. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 22: Vertical Distribution of Temperature > Conditional Stability: WALR < ALR < DALR > p. 299