Modelled and observed velocities are always an average over an interval of time - a day in the case of Australia’s operational system. But users typically require estimates at shorter intervals than this so that the effects of tides, inertial oscillations and other atmospherically-forced motions are represented.
The FOO recommends that operational forecasts be available at hourly intervals, with tides included. The problem here is whether the sub-daily variations are accurate, or merely realistic.
The FOO recommends that skill assessments be conducted separately for timescales ranging from multi-year to hours.