The basic structure of an MCS, including front to rear sloping updraft and rear to front sloping downdraft, are explainable as a gravity wave response to thermal forcing, according to Pandya and Durran (1996; JAS). However, many other authors have been demonstrating the essence of convective systems to be dynamics driven by potential vorticity anomalies. Which is it? Insight on this matter is gained through many numerical experiments applying specified heating distributions in a nonhydrostatic numerical model.
Under conditions of anticyclonic ambient rotation, or equivalently, undisturbed low-latitude flow, the updraft responding to the heating coupled with an outward propagating gravity wave, resulting in a broader, lower mean updraft, with much of the extra upward mass flux occurring outside heating centers. Such a pattern would favor in-situ development of a broad stratiform region and the low altitude of peak updraft perhaps would favor warm rain efficiency. Under conditions of cyclonic ambient rotation, as might be characteristic of convection developing in a strong wave disturbance, the heating does not couple to gravity waves, a strong diabatically generated mesoscale vortex forms, the updrafts are exclusively in heating cores. Gravity wave dynamics govern the former case while the mesoscale vortex is the dominant feature in the latter case.
Other experiments suggest more of a hybrid. The mesoscale vortex becomes more balanced and is able to survive long after heating is discontinued due to the role of thin internal waves in the adjustment process, serving to reduce the Rossby radius. So an interplay between gravity wave dynamics and a vortex-dominated system is at work. In one experiment with a particularly strong, deep diabatic vortex, time-height and time-radius cross sections of vertical motion give the impression the entire system is behaving as a gravity wave. Other more subtle features of vortices are also related to gravity waves in some experiments.
NOTE: I am sole author on both this and another modification to this conference. I understand that some conferences restrict first authors to one presentation per conference. I give my other modification higher priority. Additionally, please consider that I am not co-author on any other modifications and I have not presented at an AMS conference in several years, and I would be willing to accept poster presentations for this if that would help accommodate my being able to present both papers.