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Recent observations have shown a positive correlation between rotating flow and higher rain rates associated with mesoscale convective organization. The ability of convection and heavy rain to enhance rotation can be understood through the direct effects of vortex stretching and convective heating, but the reverse influence of rotation on convection is more complicated and indirect. Multiple physical mechanisms can lead to enhanced convection associated with mesoscale potential vorticity (PV) anomalies, including isentropic uplift, mesoscale pressure perturbations, boundary layer pumping, moisture advection, and interactions with larger scale environmental flow. These mechanisms are not mutually exclusive, leading to complex vertical motion patterns that are difficult to ascribe to any single factor. In this talk, the relationships between PV, moisture, and convection will be explored using theory, idealized modeling, and field campaign observations. A novel approximation for balanced weakly rotating flow will be presented that provides a theoretical framework for understanding vertical motion in tropical disturbances, including the mei-yu front, easterly waves, and tropical cyclones. Idealized modeling and observations are used to examine the positive feedback between rotation and heavy rainfall, in which PV promotes convection that further amplifies the PV through convective heating. The feedback becomes more effective with increased rotation and can lead to cyclogenesis.
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