National Weather Service – Short–term Ensemble Enhancements

Riverside Technology, inc. (RTi) supports the National Weather Service (NWS) in various efforts to enhance the functionality, code, and documentation of various modules of the National Weather Service River Forecasting System (NWSRFS), including various aspects of its ensemble streamflow prediction (ESP) functionality. The purpose of this project was to further enhance various short-term ensemble functions within NWSRFS.

The first enhancements were to modify the Extended Streamflow Prediction Analysis and Display Program (ESPADP) and BatchBuilder to view deterministic and probabilistic forecasts together for all plot types and modify x-axis labels to display every 24 hours. RTi staff examined the program to determine which plots already did this and which did not. Code for one of the fully functioning plots was reviewed as an example of the approach required for integration of the forecasts. BatchBuilder also was modified, allowing the user to create an ESPADP batch file including a request for the combination plot. RTi also revised the short-term mode plotting so that labels are applied every 24 hours, rather than using the old scheme, in which labeling interval was a function of the plotting window.

The second set of enhancements were to modify ens_pre_s to issue forecasts at times other than 12Z and allow a user to specify a single value Quantitative Precipitation Forecast (QPF). An algorithm for scanning the fs5files for observations was incorporated. Logic was added to ens_pre_s to determine the start date for ensemble construction and add QPF values. Additional development replaced output values in the precipitation and/or temperature ensembles with observed values found in the fs5files for each time step for which observations are available. RTi staff tested these enhancements using a variety of configurations.

2290 East Prospect Road, Suite 1, Fort Collins, Colorado 80525
phone: (970) 484–7573  fax: (970) 484–7593 www.riverside.com