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Simulating Hail and Lightning over the Alpine Adriatic Region - A model Intercomparison Study
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  • Barbara Malecic,
  • Marie-Estelle Demory,
  • Kristian Horvath,
  • Damjan Jelic,
  • Christoph Schär,
  • Maja Telišman Prtenjak,
  • Patricio Velasquez,
  • Nikolina Ban
Barbara Malecic
Universtiy of Zagreb, Faculty of Science

Corresponding Author:[email protected]

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Marie-Estelle Demory
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Kristian Horvath
Meteorological and Hydrological Service
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Damjan Jelic
Andrija Mohorovičić Geophysical Institute, Department of Geophysics, Faculty of Science, University of Zagreb
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Christoph Schär
ETH Zurich
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Maja Telišman Prtenjak
University of Zagreb, Faculty of Science, Department of Geophysics
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Patricio Velasquez
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Nikolina Ban
University of Innsbruck
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Hail is a significant convective weather hazard, often causing considerable crop and property damage across the world. Although extremely damaging, hail still remains a challenging phenomenon to model and forecast, given the limited computational resolution and the gaps in understanding the processes involved in hail formation. Here, eight hailstorms occurring over the Alpine-Adriatic region are analyzed using Weather Research and Forecasting (WRF) and Consortium for Small Scale Modeling (COSMO) simulations, with embedded HAILCAST and Lightning Potential Index (LPI) diagnostics at kilometer-scale grid spacing (~2.2 km). In addition, a model intercomparison study is performed to investigate the ability of the different modeling systems in reproducing such convective extremes, and to further assess the uncertainties associated with simulations of such localized phenomena. The results are verified by hailpad observations over Croatia, radar estimates of hail over Switzerland and lightning measurements from the LINET network. The analysis revealed that both HAILCAST and LPI are able to reproduce the areas and intensities affected by hail and lightning. Moreover, the hail and lightning fields produced by both models are similar, although a slight tendency of WRF to produce smaller hail swaths with larger hailstones and higher LPI compared to COSMO is visible. It is found that these differences can be explained by systematic differences in vertical profiles of microphysical properties and updraft strength between the models. Overall, the promising results indicate that both HAILCAST and LPI could be valuable tools for real-time forecasting and climatological assessment of hail and lightning in current and changing climates.