Howdy Harish Gopalan,

Given your skills and background, as provided by your ResearchGate profile, it is clear that you are aware that a simple answer may be misleading and must be applied with care. That written, it is likely that you would like to recognize or expect the presence of squall lines in your computer models without including the required mesoscale dynamics to treat them.

I suggest you throw a large stone in a still pond and note not only the principal wave from the impact site, but also the smaller waves running in front of it. Think of the principal impact wave as a simulation of a cold front forcing its way into/under the warm sector of a storm. The smaller leading waves from the splash of the stone simulate waves in the atmosphere running ahead of the cold front. These waves trigger convection by lifting and initiate the thunderstorms of a squall line in this thought experiment.

This is heuristic, a guide to a movie in your mind's eye that triggers a squall line ahead of the front. Use it with care because reality is more complicated than this simple movie and often very different.

Happy Trails, Len

Leonard provided the mechanisms of the formation of squall lines in the mid-latitude and extratropical regions. In the tropics, they can be attributed to the easterly tropical waves. In the atmosphere, they can be viewed as a series of convective clouds that influence heavy thundershowers, and sometimes flooding events (depending on the location's topography).

Leonard Hall and Philbert Modest Luhunga Thank you for your comments.