Convective-scale warn-on-forecast system: A vision for 2020

Warning about convective-scale hazards are based on observations, and it is essential to develop warning methods in which numerical model forecasts play a larger role. High resolution numerical weather prediction models can potentially provide warning information on the future evolution of storms and their internal structure, thereby increasing convective-scale warning lead times. It is essential that the model be started with a very accurate representation of ongoing convection to obtain the necessary one-to-one correspondence between model-predicted and observed thunderstorms. The introduction of the national network of Doppler radars in 1990s and the ability to transmit, composite, and merge all the radar data in near-real time allow for the assimilation of in-storm Doppler radar reflectivity and radial velocity observations into convective-scale forecast models. A warn-on-forecast system is predicted that assimilates observations of convective storms and their environments into an ensemble of convective-scale numerical weather prediction models.