It is also found that the precipitation anomalies in SMDs are highly correlated in space with column-integrated water vapor. Based on this correlation, we analyze the column moisture and frozen moist static energy (MSE) budgets as proxies for the propagation of the precipitation anomalies. Propagation of the moisture anomalies is dominated by vertical moisture advection while the MSE anomalies propagate due to horizontal advection of dry static energy by the anomalous winds. By combining the budgets, we interpret the propagation of the precipitation anomalies in terms of lifting that is forced by horizontal dry static energy advection, that is, ascent along sloping isentropes. This process moistens the lower free-troposphere, producing an environment that is conducive to deep convection. Longwave radiative heating is the main mechanism for maintaining MSE and precipitation anomalies.
Supplementary URL: https://journals.ametsoc.org/doi/abs/10.1175/JAS-D-17-0309.1