Papers of note: Involving humans in the ensemble forecasting of severe weather

The NOAA SPC/NSSL Spring Program 2003 tested an ensemble generation method in which human forecasters were involved in the ensemble creation process. A customized ensemble provided guidance on the severe weather threat over the following 48 h. Using an adjoint, a set of perturbations was obtained and used to generate a 32-member ensemble. Results show that the experimental ensemble improves upon the operational numerical forecasts of severe weather and produces better probabilistic forecasts of heavy precipitation.