The integrated effect of condensation in numerical simulations of extratropical cyclogenesis

Each storm featured a weaker cyclonic low-level circulation when latent heating was removed from the simulation, but the magnitude of the effect varied greatly. In all cases, the difference in intensity was attributed to velocities associated with a positive, condensation-produced PV anomaly above the warm front. The amplification of the surface thermal perturbations was not strongly altered in even the case most affected by condensation. Hence, the primary effect of condensation at low levels was simply to superpose a positive PV anomaly into the cyclonic circulation that would exist without latent heating. The feedback of latent heating onto the interaction of tropopause PV and surface potential temperature anomalies appears small. -from Authors