We describe a prototype system for medium range (up to two week lead) flood prediction intended for use in large rivers, primarily outside the developed world where in situ data are sparse. Our vision is to rely heavily on weather prediction model output, and satellite remote sensing, which will reduce the need for in situ precipitation and other surface observations in parts of the world where a hydrologic forecast capability arguably would have the greatest value. The hydrologic component of the system is the Variable Infiltration Capacity (VIC) macroscale hydrology model. In the prototype, VIC generates hydrologic states for forecast initialization using daily ECMWF analysis fields for precipitation, wind, and surface air temperature, all of which are bias corrected to be consistent with ECMWF ERA-40, which are treated as climatology. In hindcast mode, VIC is driven by global ECMWF Ensemble Prediction System 10-day forecasts that are bias corrected with respect to ERA-40 data as well, and spatially disaggregated using two higher spatial resolution satellite products: Global Precipitation Climatology Project (GPCP) 1dd daily precipitation and Tropical Rainfall Measuring System (TRMM) 3B42 precipitation. The prototype system is implemented globally at one-half degree spatial resolution, and tested for selected large river basins during the 2002-2007 period. In particular, we focus on evaluation sites within the Mississippi River basin because the in situ data network is relatively dense, and offers a good opportunity to evaluate the global system which is based on much sparser in situ data. In our evaluation, we focus on floods within the Mississippi Basin that occurred between 2002 and 2007.