Climatologically-based QPF Box Plots
The climatologically-based QPF used as input after 48 hours, is much different. The ensemble spread is smaller and the spread often does not include the zero line for the medium and large values. This means that the climatologically-generated QPF rarely captures the true precipitation for moderate and heavy events.
The underforecast bias and the lack of ensemble spread in these climatologically-based QPF are consistent with the underforecast and lack of spread seen in the hydrologic forecast at long lead times for high flows.
There is also some overforecast of the low-end values, consistent with the overforecast bias seen in the long lead-time hydrologic forecasts.
This helps to confirm that QPF may be a big source of error in the hydrologic forecast process.
