BOM declares a La Niña, signalling wet spring and summer likely for northern, eastern Australia
Criteria for La Niña declaration:
Sea surface temperatures in regions of the eastern Pacific are 0.8C cooler than average
Trade winds have been stronger than average in the western or central Pacific during any three of the past four months
Southern Oscillation Index, a measure of the difference in pressure between Tahiti and Darwin, is +7 or higher
Majority of climate models show sustained cooling of at least 0.8C below average in the eastern pacific until the end of the year
What does this mean for cyclone season?
The warm waters and increased convection also lead to La Niñas being associated with increased numbers of cyclones.
In a normal year we see roughly between nine and 11 tropical cyclones in Australian waters.
But according to Dr Watkins, we could be in the upper end or even above that range this year.
"That also increases the risk of tropical cyclones crossing the coast, so lots of impacts of La Niña, particularly as we get into summer." Will farmers be able to get crops out?
After the past few years of drought on the east coast, recent months of good rains for the south-east have been welcome.
The forecast of more rain will be welcome for those who have so far missed out in 2020.
