Using High-Resolution Ensemble Precipitation Data to Develop New Probabilistic Hazard Information at the Weather Prediction Center

Recent increases in the availability of convection allowing models (CAMs) have paved the way for innovative ways to use and display this high-resolution data. This can aid the forecaster in better synthesizing the ensemble of possible solutions, resulting in a more calibrated and efficient forecasting process. The Weather Prediction Center (WPC) is particularly interested in quantitative precipitation forecasts (QPF) from CAMs to aid in the generation of their forecast products. However, QPF can be challenging since precipitation typically takes the form of coherent objects, resulting in more complicated structures than for other variables like temperature or geopotential height. Furthermore, the relationship between QPF amount and flash flooding is not very straightforward.

To address both of these problems, this talk will detail the preliminary work of two United States Weather Research Program (USWRP) sub-projects. The first subproject, which is part of “Probability of What?” will explore the development of new Probabilistic Hazard Information (PHI) by coupling an ensemble of quantitative precipitation forecasts (QPFs) to a hydrologic model. This talk will show some results from a few high impact case studies including Hurricane Matthew in 2016 and the Oklahoma-to-Indiana flooding event in April 2017. A second USWRP sub-project within the larger “Refinement and Evaluation of Automated High-Resolution Ensemble-Based Hazard Detection Guidance Tools for Transition to NWS Operations” focuses on tracking ensemble QPF objects through time and collects their object attributes in order to generate new visualization products for WPC forecasters. This talk will show some QPF tracking results with the Model Evaluation Tools (METv6.0) software package using the High Resolution Rapid Refresh (HRRRv2 and HRRRv3), the High Resolution Ensemble Forecast (HREFv1 and HREFv2), and the National Severe Storms Laboratory (NSSL) ensemble. Plans on integrating these new techniques into operations will be discussed.