An 18‐year climatology of hailstorm trends and related drivers across southeast Queensland, Australia

Abstract

The southeast Queensland (SEQ) region of Australia is recognised for frequent thunderstorms documented through numerous studies including high-impact severe thunderstorm cases which have caused insured losses exceeding $1 billion AUD. Despite a modest body of scientific literature, basic questions regarding the role of climate, synoptic and local-scale (<10 km) processes affecting the variability of thunderstorms still remain. In an effort to advance these questions as part of the Coastal Convective Interactions Experiment (CCIE), this study integrates multiple datasets across an 18-year period (July 1997-June 2015) to provide a mesoscale climatological analysis of the SEQ hailstorms and associated environmental conditions. On a multi-year time-scale, the relationship between the El Niño Southern Oscillation and hailstorm frequency is consistent with previous studies. On synoptic scales, a southeasterly change situation coupled with a sea breeze was found to provide the most favourable environment for hailstorms, particularly for southwest SEQ. On the local scale, hail development within convective cells was found to be most frequent within the inland limb of the maritime air mass on sea-breeze days. This observation suggests the sea-breeze air masses may become favourable for convection after sufficient modification during inland propagation.

Understanding Hail in the Earth System

“…Radar also provides an excellent methodology to obtain a proxy representation of hail swath data which has seen increasingly wide application around the world (e.g. Cintineo et al, ; Lukach et al, ; Nisi et al, ; Ortega, ; Puskeiler et al, ; Soderholm et al, ). Given the extending length of climatologies of this kind, it is likely that the radar‐derived occurrence will play an important role in defining climatological frequency in the years to come, and in providing a climate quality record that is independent of the problematic surface observations.…”

“…In Australia, Doppler radar has only been recently implemented for a wide array of sites, and hence, the nationwide availability of climatological length records is limited. Given the propensity for hailstorms in southeast Queensland, analysis using radar data and MESH‐derived climatology for 18‐years has been developed over the Brisbane region (Soderholm et al, ; Soderholm et al, ), with work ongoing to expand these studies to Sydney and Melbourne. These climatologies have illustrated the importance of sea breeze fronts for initiating the development of organized storm updrafts in this region (Soderholm et al, ).…”

Quantifying Hail and Lightning Risk Factors Using Long‐Term Observations Around Australia

“…There is a need for improved preparedness for convection‐related hazards including through greater understanding of their meteorology, mean occurrence frequencies, and environmental factors influencing their spatiotemporal variability. In Australia, previous studies have investigated the mean occurrence frequency of hail through analysis of radar observations near Brisbane and Sydney (Soderholm, McGowan, Richter, Walsh, Weckwerth, et al, 2017; Warren et al, 2020), satellite observations (Bedka et al, 2018; Cecil & Blankenship, 2012), as well as station observations and damage reports (Allen & Allen, 2016; Prein & Holland, 2018; Schuster et al, 2005, 2006). The mean occurrence frequency of lightning over the Australian region has been examined based on satellite observations (Bednarczyk & Sousounis, 2014; Dowdy & Kuleshov, 2014) and station observations (Bates et al, 2015).…”

A radar‐based study of severe hail outbreaks over the contiguous United States for 2000–2011

“…Their successful use of MESHS, along with other studies such as Soderholm et al . (), shows the international importance of such radar‐based hail proxies in areas where reporting networks are sparse. Studies by both Cintineo et al .…”