Automatic Forecast Verification in WSFS

Juha Markkula, Bertel Vehviläinen

SYKE

20.04.23

Automatic Forecast Verification in WSFSWatershed Simulation and Forecasting

System (WSFS) has a separate subsystem to automatically calculate verification graphs and scores for operational forecasts.

This subsystem is called Forecast Accuracy Follow-up System (FAFS)

Forecast Accuracy Follow-up System (FAFS) Verification is based on released operational

forecasts, not on hindcasting FAFS has a web interface where

hydrologists can go back to previous incidents and see how the forecasts succeeded.

FAFS web interface

Lake inflowRiver peak flowAnd less important ones

• Groundwater level• Lake inflow in test model based on monthly/seasonal

weather forecast• Short meteorological temperature forecast

Lake inflow

Lake inflow

Lake inflow

Lake inflow

Lake inflow

Lake inflow

Lake inflowMost important forecast verification criteria

Mean absolute error:

Relative error:Mean absolute error divided by range of observations

Nash – Sutcliffe:

River peak flow

River peak flow

River peak flow

River peak flow

River peak flow

River peak flow

River peak flow

River peak flowDischarge forecast: 7 day lead time,intended to display peak timing error.

River peak flowDischarge forecast: 7 day maximum discharge,intended to display error in peak discharge.

River peak flow

Most important forecast verification criteria

Peak timing error:Mean absolute error in peak timing.

Peak discharge error:Mean absolute error in maximum discharge.