A Comparison of the Current and Next Version of the HRRR for Some Recent High-Impact Mesoscale Events

The next upgrade for the High Resolution Rapid Refresh (HRRR) model at the National Centers for Environmental Prediction (NCEP) is scheduled for mid 2020. A number of changes will be part of the next version of the HRRR and will be covered in separate talks from other members of our group. Since the code handoff to NCEP occurs well before the scheduled operational implementation, many of the changes have been in place for some time within a parallel experimental version of the HRRR (HRRRX) that is run at ESRL/GSD. This presentation will compare forecasts from the HRRRX with those from the current operational HRRR for a variety of significant and typically challenging weather events. We will include mesoscale events ranging from winter snow bands to severe convective outbreaks as well as heavy rainfall. Subjective comparisons such as these compliment the ongoing objective verification that is part of the HRRR assessment. They also help to demonstrate the impact of some of the changes in the newest version of the HRRR. Of course, there remain some forecast scenarios that are challenging, and we will show some of these issues within the cases that are selected.

This presentation will complement other HRRR presentations that will discuss various aspects of the HRRR and the changes that will be made in the next operational HRRR in more detail.