Improvements of convective parameters calculation algorithms in thundeR

The ThundeR rawinsonde processing package is a free, open-source R package designed for the visualization of atmospheric soundings and hodographs, as well as for the rapid calculation of convective parameters which are widely used in both research and operational forecasting of severe convective storms.

The package can calculate over 300 parameters in realtime (~1/100 s), enabling efficient processing of large numerical datasets. In recent years, ThundeR has been applied to global reanalysis datasets, operational numerical weather prediction models, and studies of environments associated with lightning observations and severe weather reports across Europe, North America, South America, and Australia.

ThundeR has also contributed to the development of ESSL’s AR-CHaMo models and has been utilized by severe storm researchers in multiple countries, including national hydrometeorological services. The construction of environmental datasets collocated with severe storm observations from various regions has provided a robust platform for evaluating the predictive skill of hundreds of convective parameters. This framework has also supported the iterative development and testing of new parameter concepts.

In this work, we present modifications to the calculation procedures of several established parameters, leading to improved identification of environments conducive to lightning, large hail, tornadoes, and severe winds, including significant severe events. These updates include refinements to the computation of convective inhibition, lifted index, and storm-relative helicity, as well as the introduction of a new ventilation parameter and two novel parcel-lifting methods: most-unstable mean-layer (MUML) and most-unstable above 500 m (MU5).

Finally, we demonstrate how these advancements can be applied in operational forecasting of severe convective storms and in modeling their climatology on a global scale.