Paper evaluating different schemes to predict convection in hurricanes published in Weather and Forecasting

Forecasters and researchers use the Hurricane Weather Research and Forecasting (HWRF) model to forecast where a hurricane will go, how strong it will be, how large it will be, and where the strongest winds are. Hurricanes are made up of thunderstorms (what we call convection), but individual thunderstorms are too small for the models we currently use. So, we use a process called parameterization to estimate the thunderstorms in the model forecast. This paper looks at how the parameterization of convection in hurricanes affects forecasts of hurricanes. We ran HWRF many times, using two different parameterizations, to see which forecasts are closest to observations that we obtained from NOAA Hurricane Hunter Aircraft. Then, we looked at why the the two parameterization schemes make different forecasts in HWRF. The study emphasizes the importance of convective-scale processes in and around TCs to improve model intensity forecasts.

Important Conclusions:

1. Accurate parameterization of convection in HWRF is important for forecasts of how strong a hurricane will get.
2. The Grell-Freitas (GF) convective scheme performed better than the Simplified Arakawa Schubert (SAS) for forecasts of hurricane track and intensity according to these HWRF forecasts.
3. The GF scheme causes stronger flow into the hurricane at low levels than the SAS scheme.
4. The temperature increase in mid-upper levels is larger in the GF scheme than in the SAS scheme.

The study can be found at https://journals.ametsoc.org/doi/abs/10.1175/WAF-D-19-0124.1.