Model Certainty: Using Multimodel Ensembles for Integrated Decision Support Services

A cornerstone of the National Weather Service (NWS) strategic plan is to increase Impact-Based Decision Support Services (IDSS) that assist core partner decisions when weather, water and climate impacts lives and livelihoods. One critical method of providing IDSS is the communication of certainty information of impending weather situations. While ensemble information exists through multiple ensemble forecast systems, these data are difficult to access through the NWS’s Graphical Forecast Editor (GFE) program within the Advanced Weather Interactive Processing System. As a result, the “Model Certainty” tool was developed to provide this valuable information to forecasters.

GFE provides forecasters a gridded multi-model ensemble with upwards of 30 raw and bias- corrected model outputs during the short term portion of the forecast (hours 0 to 72), when IDSS needs are at their peak. The Model Certainty tool quickly produces Cumulative Density Functions, Probability Density Functions, box and whisker plots, and wind roses for weather elements such as hourly temperature, dewpoint, relative humidity, wind, apparent temperature, maximum and minimum temperature, snow amount, and quantitative precipitation forecasts. This presentation will focus on the methods forecasters use to interrogate this statistical information to inform watch, warning and advisory decisions, and provide certainty information to core partners.