Heavy versus extreme rainfall events in southeast Australia

Focussing on the major cities of Brisbane, Sydney, and Melbourne in southeast Australia, this study seeks to determine environmental factors that distinguish between heavy rainfall events (HREs) extreme (EREs). Using daily rain gauge observations, HREs EREs are defined for each domain based, respectively, 95th 99th percentiles wet-day period 1979–2018. K-means clustering is applied mean sea-level pressure, data from ERA5 obtain a set representative large-scale circulation patterns associated with these events. Composite synoptic maps, vertical profiles, series column-integrated diagnostics then examined cluster used compare characteristics EREs. For all three cities, an upper-level trough west, ascent, positive column water vapour (CWV) anomalies, strong moisture transport over analysis domain. Brisbane clusters characterised by coastal trough/low moist onshore flow Tasman Coral Seas. Melbourne, more distinct, front, cut-off low, inland trough. Compared HREs, show amplified trough, stronger motion larger CWV anomalies In also feature deeper flow, promoting enhanced transport. A diagnostic termed upward transport, which combines key ingredients high shown discriminate well domains. contrast, surface temperature, frequently linked extremes via Clausius–Clapeyron scaling, shows significant overlap different event categories, particularly Sydney.