1992 Queensland Storms - Climatology and Conditions

Climatology and Conditions

November is traditionally the start of the thunderstorm season along the eastern seaboard of Australia, with a rise in average humidity and warmer ground temperatures combining with more frequent occurrences of cool air in the upper atmosphere. These conditions are conducive for producing severe thunderstorms, particularly those which feature hail.

The conditions on Sunday, 29 November were extremely unsettled. There were a series of thunderstorm cells that formed early in the morning — despite it being more common for thunderstorms to form in the late afternoon in the south-east Queensland region. These storms, which had periodic bursts of severe lightning, cleared quickly.

Thunderstorms began to form again just before midday, as the hot and humid conditions became more acute in the middle part of the day. The Bureau of Meteorology radar picked up a series of cells to the north-west of Brisbane, the capital of Queensland, and the data suggested that there was a possibility of large hail. The Bureau immediately issued a Severe Thunderstorm Warning for the coastal region between Brisbane and the Sunshine Coast, 100 km to the north.

The main cell in the thunderstorm system appeared from Bureau of Meteorology radar analysis to split into two separate and distinct cells. This development resulted in one part of the major storm to head north, to Maroochydore, while the other part headed south towards Brisbane. The southern cell struck Brisbane just after 1:00pm, with intense lightning activity and hailstones the size of marbles falling. The storm caused a lengthy delay during the First Test of the series between Australia and the West Indies, when hail forced play to be stopped at the Brisbane Cricket Ground around 1:15pm.

The northern cell continued to intensify throughout the afternoon. The Bureau of Meteorology then recognised it as a supercell, which often bring erratic developments and often last for long periods of time. The storm dropped hailstones which were between eight and ten centimeters around Maroochydore, on the Sunshine Coast, damaging the roofs of around 80 houses in the area. The hail also damaged aircraft at a local airport and dented cars, as well as inflicting injuries to a handful of swimmers at beaches near Maroochydore.