Researching the Hail Out of Storms: Using Models & Observations to Improve Understanding & Prediction of a High-Impact Hazard

Dr. Kumjian's seminar

Prof. Matthew Kumjian

Department of Meteorology and Atmospheric Science

Pennsylvania State University

Monday October 17, 2022, 2 PM ET



Hail is the costliest hazard produced by deep convective storms, producing over $20 billion in insured losses on average annually in the United States alone. Although conditions favoring the parent hailstorms are relatively well understood and predictable, a given storm’s propensity to produce damaging hail — and the degree and nature of that storm’s hail risk — remain highly uncertain, posing a formidable forecasting challenge. These uncertainties arise owing to numerous factors, including the inability of operational models to explicitly represent hail processes, an unreliable and biased ground truth database, and an incomplete fundamental scientific understanding about what environments, storm structures or behaviors, and microphysical processes are conducive to hail production.

To tackle these problems, we take a multi-pronged approach. Using high-resolution, idealized numerical model simulations of hailstorms, combined with a detailed hail trajectory growth model, we uncover environmental and storm behavioral controls on hail production. With state-of-the-art technology from field observations, we are able to obtain detailed three-dimensional digital models of hailstones that can be used for refining microphysics parameterizations of hail growth processes, and improve remote-sensing-based algorithms for hail detection and sizing. In this talk, we will review our current understanding of hail formation and growth in deep convective storms, and present our recent findings on what factors control the amount and size of hail produced — and the physical processes underpinning these controls.



Dr. Matthew Kumjian is an Associate Professor in the Department of Meteorology and Atmospheric Science at The Pennsylvania State University. His research foci include precipitation physics, radar remote sensing, and mesoscale meteorology. Dr. Kumjian received the 2020 Henry G. Houghton Early Career Award from the American Meteorological Society for his contributions towards advancing our understanding of precipitation physics processes with novel applications of dual-polarization radar observations, as well as an AMS Editor’s Award for Monthly Weather Review and Weather and Forecasting in 2016. He currently serves as an Editor for Monthly Weather Review. Dr. Kumjian has taught undergraduate and graduate classes at Penn State on Cloud Physics, Radar Meteorology, Mesoscale Meteorology, and Snow & Ice Physics, and developed and taught courses on Precipitation Physics, Atmospheric Optics, and Aerosol-Cloud-Precipitation Interactions. He lives in State College, Pennsylvania with his wife Kelly and stepdaughter Emily, and enjoys hiking, playing in the snow, observing the menagerie of birds and animals in the backyard, and spending time with his family.



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Oct 17 2022


John Xun Yang