Major Risks, Uncertain Outcomes: Making Ensemble Forecasts work for Multiple Audiences

Research Study of NWS Ensemble Forecast Products

Through a grant to East Carolina University from NOAA’s CSTAR program, Nurture Nature Center in 2016 undertook its third social science research study of NWS Products. This project, “Major Risks, Uncertain Outcomes: Making Ensemble Forecasts work for Multiple Audiences,” used focus groups and surveys with residents and emergency managers in West Virginia and Maryland to understand how NWS’ Hydrologic Ensemble Forecast System works and could be improved for various audiences.

For those living or working in communities near rivers and streams, having inforfmation about forecast water levels is critical for planning. Property owners and emergency managers need to know if a flood is possible or imminent, while water resource managers need detailed information to control infrastructure and water supply. While National Weather Service (NWS) deterministic forecasts, represented as a hydrograph, are a go-to resource for decision makers, often it is useful to know the full range of possible levels that could occur, and understand the inherent uncertainty in river forecasts at longer timeframes.

This study tested a suite of products from NWS’ emerging Hydrologic Ensemble Forecast System (HEFS) which provides short and long-range forecasts showing uncertainty. The goal of the study was to assess the utility of some newly developed HEFS products (15 day and 90 day timeframes) and identify any barriers to proper understanding of the understandability and accessibility for various users.

The research team held focus groups in Jefferson County, WV and Frederick Copimty, MD with emergency managers and residents, along with online sessions for water resource managers, leading participants through a 4-day extratropical storm scenario illustrated with various NWS products, including the HEFS. Multiple sessions and surveys allowed for testing of revisions to the graphical design of the suite of products and for assessment of the utility and understandability of the products.

Final report with findings can be viewed here. A printable one page overview of the project and findings is available here.

(Funded to East Carolina University via NOAA Award NA16NWS468000, May 1, 2016, with subcontract to Nurture Nature Center.)