Convective parameters for severe weather forecasting and research in Australia

The Australian Bureau of Meteorology (BoM) has recently operationalized a post-processing suite called ConvParams, which computes a wide array of convective parameters using output from the BoM’s global deterministic and ensemble NWP models. Outputs from the suite include parcel parameters such as CAPE and CIN (computed for a range of different initial parcels), kinematic diagnostics such as bulk wind difference and storm-relative helicity (computed for a range of different atmospheric layers), and composite indices such as the supercell composite parameter and significant tornado parameter. In addition, the suite also identifies important features in the atmospheric profile such as capping inversions and elevated mixed layers. A unique feature of ConvParams, compared to other similar codebases (NSHARP/SHARPpy, MetPy) is its use of high-order polynomials to approximate pseudoadiabatic processes, which permits parcel calculations that are both fast and highly accurate. Significant computational advantages also come from the use of an ahead-of-time compiler (Pythran), which “transpiles” the native Python code into fast C++ code. As well as being used in operations, ConvParams is being run as part of the second-generation BoM Atmospheric Regional Reanalysis for Australia (BARRA2), a regional downscaling of the ERA5 reanalysis, and the BoM Atmospheric Regional Projections for Australia (BARPA), a regional downscaling of CMIP6 climate projections. Once complete, these simulations will provide the most comprehensive picture of historical and future convective environments in Australia to date, supporting major research in this space over the coming years. This presentation will provide an overview of the ConvParams suite and highlight its applications in both operational forecasting and future research endeavours.