BoM says big wet over for now but La Nina may be back later this year
Richard Dinnen - Queensland Editor |
The Bureau of Meteorology (BoM) says the La Nina event that brought record rainfall and floods in eastern Australia is over but could return later in the year.
The event began last November. In its regular climate driver update, the BoM said most indicators show it has ended, but forecast models suggest the La Nina may reform in late 2022.
The chance of that occurring is rated at 50 per cent, approximately double the normal likelihood.
La Nina and El Nino are key drivers of Australia’s climate variability, operating in a natural cycle known as the El Niño-Southern Oscillation (ENSO).
El Nino periods are drier, while La Nina events bring increased rainfall across much of Australia, shifts in temperature extremes, more cyclones, and an earlier onset of the monsoon.
Most climate models surveyed by the Bureau indicate ENSO is likely to remain neutral through the southern hemisphere winter.
But four of the seven models suggest La Niña could return in spring, raising the possibility of a rare three consecutive events. That’s only been recorded three times before.
La Niña was associated with record floods that hit northern New South Wales and southern Queensland in late February and early March.
The BoM climate update said sea surface temperatures are currently warmer than average around much of the Australian coastline, particularly to the north and west, increasing the chance of above average winter and spring rainfall.
It said Australia’s climate had warmed by almost 1.5 degrees Celsius for the period 1910–2020, with less cool season rain in southern regions, and more rain coming from high intensity short duration rainfall events, especially across northern Australia.
