  In the backdrop of a revolution in weather prediction by Numerical Weather
Prediction (NWP) models, quantitative prediction of intensity of heavy rainfall
events and associated disasters has remained a challenge. Encouraged by
compelling evidence of electrical influences on cloud/rain microphysical
processes, here we propose a hypothesis that modification of raindrop size
distribution (RDSD) towards larger drop sizes through enhanced
collision-coalescence facilitated by cloud electric fields could be one of the
factors responsible for intensity errors in weather/climate models. The
robustness of the hypothesis is confirmed through a series of simulations of
strongly electrified (SE) rain events and weakly electrified (WE) events with a
convection-permitting weather prediction model incorporating the electrically
modified RDSD parameters in the model physics. Our results indicate a possible
roadmap for improving hazard prediction associated with extreme rainfall events
in weather prediction models and climatological dry bias of precipitation
simulation in many climate models.
