QPF Box Plots

The box plots of the flow forecasts showed three phases. These are:

  • Phase 1� Before QPF forecasts have much impact there is low spread in the ensemble flow forecasts
  • Phase 2� When QPF has an impact there is greater spread in the hydrologic forecast ensemble members along with some overforecasting bias at low flows
  • Phase 3� At longer lead times when climatologically generated QPF dominates there is more underspread and a conditional bias with overforecasting for the low flow values and underforecasting for the high flow values.
Barge on river.