About HHFS hydrological forecast


Tables present observed data (where possible at 07 CET) and forecasted water level values. Bold values show the most probable forecast values, while grey intervals indicate the reliability of the forecasts. The error interval is defined based on the last years' forecast errors. Since forecast errors can be described by normal distribution function, it is expected that water levels remain within the error interval with the probability of 70%.

At certain gauges close to the spring or gauges on high altitudes water level rising usually occurs within a short time. Consequently, hydrological regime at these gauges is defined by the performance of the meteorological models, mainly precipitation forecast. Since uncertainties of both precipitation and hydrological forecasts can increase significantly with lead time, hydrological forecasts with several days lead time can contain higher uncertainties than the average uncertainties indicated by the error interval and thus they are rather intented to draw attention to the possibility of the predicted hydrological situation.

In order to highlight the uncertainties of precipitation forecasts, lead time of hydrological foreacasts is divided into two parts. The first part (marked with light grey color) presents shorter lead time hydrological forecasts caused by meteorological events occured in the past period. In the second part (marked with dark grey color) longer lead time hydrological forecasts are presented which mainly rely on meteorological forecasts, thus their accuracy strongly depends on the performance of the meterological forecast model. The proportion of the two parts basically depends on the concentration and propagation times at the given gauge.

For gauges situated in backwater reaches another significant error source can be the artificial water regime resulted from the unknown working program of power plants.

Observed and forecasted water level values might exceed alert levels or the HHW level, or they might decrease under the LLW level. In order to draw attention to these superventions these levels are marked with certain colours.

  • Exceed 1st alert level: yellow
  • Exceed 2nd alert level: orange
  • Exceed 3rd alert level: red
  • Exceed HHW level: purple
  • Decrease under LLW level: blue