An object-based assessment of the High Resolution Rapid Refresh Model over the western US

Abstract:

The High Resolution Rapid Refresh (HRRR) model is an hourly-updated, radar-initialized, 3km storm-resolving model run operationally in the US since September 2014, with the main goal of improving forecasts of convective precipitation. Here, we identify precipitating objects in the forecast and observed fields in a manner similar to the Method for Object Based Deterministic Evaluation (MODE). The identified objects are used to perform an assessment of HRRR model forecasts of warm season convective precipitation over the complex terrain of the western US (west of 105W). The constellation of satellites comprising the Global Precipitation Measurement (GPM) Mission provide observations of precipitating objects in the domain, and can be used to assess not only the quality of the rain/no-rain forecast, but also the model’s representation of the microphysical and other environmental properties governing precipitation behavior (e.g. latent heating, vertically integrated liquid, etc.). Special attention will be paid to vertical profiles of liquid and ice water contents that can be inferred from the observed reflectivity profiles of the GPM Dual-frequency Precipitation Radar (DPR) and other imaging and sounding instruments. Potential relationships between these properties and the success or failure of the model forecast will be discussed.