The Houston Derecho: A HRRR Versus MPAS Case Study as Part of The NOAA Hazardous Weather Testbed Annual Spring Forecast Experiment

Every year in May, NOAA’s Hazardous Weather Testbed (HWT) Experimental Forecast Program (EFP), under the guidance of the Storm Prediction Center (SPC) and National Severe Storms Laboratory (NSSL), conducts the Spring Forecasting Experiment (SFE). Scientists and stakeholders use the SFE to accelerate the transfer of promising new tools from research to operations, inspire new initiatives for research, and document performance of forecast modeling systems.

This research project will focus on the operational High Resolution Rapid Refresh (HRRR) model and three different configurations of the Model for Prediction Across Scales (MPAS), which is currently undergoing rapid development. The HRRR and the three MPAS variations differ in their initial conditions and microphysics and will be both subjectively and objectively verified..

More specifically, this research project will focus on the Houston Derecho event of May 16, 2024 as a case study to determine how well the models ran during one particularly extreme convective event.

Through this verification effort, promising results for the MPAS dynamic core were delivered. We concluded that (1) the experimental MPAS configurations are on par with the HRRR, (2) RRFS initial conditions appear on par with HRRR initial conditions, sometimes performing even better, and (3) using MPAS in a future version of the RRFS has the potential to positively impact forecasting capabilities.

With plans for operational implementation of MPAS dynamic core in the future, comparing it with the currently-operational HRRR will prove vital to ensuring it is ready. Overall, this is all in hopes of making forecasting more accurate, especially for convective weather.