The first half of an FDR model sequence is nearly identical to that of a typical real-time forecast: HEC-MetVue/MFP, HEC-HMS, and HEC-ResSim. Though there are few modifications required for real-time alternatives for FDR purposes, there are some key differences in computing the models that the user needs to be aware of. This section provides discussion on computing HEC-HMS alternatives for FDR purposes.