The Environmental Modeling Center (EMC) of the National Centers for Environmental Prediction (NCEP) has developed and is now running routinely in real time a Short Range Ensemble Forecast (SREF) system. The current system is currently composed of 10 members composed of five members from both the Eta and Regional Spectral Model (RSM) with 48 km horizontal resolution. Initial state perturbations are provided by "breeding", as for the NCEP global ensemble system, but in the context of the respective regional models. Perturbations to physics, as well as initial conditions, and inclusion of additional models are anticipated. Advances currently incorporated and those expected in the near future with regard to the SREF system and derived products will be discussed. Particular emphasis will be upon how these advances relate to the skill and utility of the ensemble based probabilities in forecasting significant weather events, such as winter storms and associated sensible weather and warm season mesoscale convective systems.