Flow chart for the three versions of WRF-Hydro running during the STEP Hydromet Experiment.
WRF-Hydro 60 min streamflow prediction from 2300 UTC on 16 July 2014 along the Front Range using WRF-3DVAR with DA and AutoNowcaster nowcasts (WRF-Hydro ANC). Color markers indicate streamflow values ranging from 0-64 m3sec-1 with red colors being the highest values.
Flood forecasts depend on knowledge of the state of atmospheric features that trigger heavy rain as well as the state of surface and subsurface water, including the heights of rivers and reservoirs and the amount of soil saturation. Although both meteorological and hydrological models have improved in detail and accuracy over recent years, they can be difficult to operate in a simultaneous and integrated (i.e., coupled) fashion. The hydrological extension of the Weather Research and Forecasting model (WRF-Hydro) is a community-based framework designed to link models of the atmosphere and terrestrial hydrology. The configuration of WRF-Hydro running in the STEP Hydromet Prediction System is ingests WRF-3DVar atmospheric model output with selected WRF-Hydro hydrology physics options to produce analyses and forecasts of water cycle processes and streamflow prediction over a range of spatial and temporal scales.
WRF-Hydro is being driven in three ways during the 2014 STEP Hydromet Experiment:
- Baseline WRF with GFS initialization (WRF-Hdyro)
- WRF-3DVar with radar data assimilation (WRF-Hydro DA)
- WRF-3Dvar with radar data assimilation and AutoNowcaster/Trident (ANC) precipitation nowcasts (WRF-Hydro ANC)
The flowchart below shows the three instances of WRF-Hydro running on the Yellowstone supercomputer. The past 3 to 6 hr rainfall accumulation obtained from the EOL radar-based QPE mosaic is used in the WRF-Hydro spin-up period.
WRF-Hydro produces 0-12 hr streamflow forecasts on a 100 m resolution grid centered over the Front Range. An example of the streamflow forecast product is shown below.