Nor Easter waves are blowing in much more
North Easterly waves known as Nor Easters are becoming more frequent.
The East Australian Current (EAC) that brings tropical warm water down from Queensland onto Sydney beaches is getting stronger.
A rise in warmer water has resulted in an upsurge of tropical fish and soft coral species in Sydney Harbour.
In the southern hemisphere, the seawater layer moves to the left of the wind direction - due to the Earth’s rotation - known as the Coriolis effect.
The hot land temperatures of summer bring in sustained Nor Easter onshore breezes, and the warm top layer starts drifting at right angles to the prevailing wind.
This overall weather con- dition has had the net effect of bringing up cold, nutrient rich water from the deeper ocean to replace it.
It usually lasts for a few days with cold water mixed with the very warm North Westerly brings about stuning sea mists.
When the southerly buster finally arrives the warm water is pushed back onshore and onto Tahiti’s back.
In 2007 a prolonged freezing water event was caused by a giant eddy the size of Tasmania, situated about 100 kilometers offshore of Sydney that was swirling around with a full rotation of 10 days.
At its centre the eddy caused an up swelling of very cold water from depths of almost 1000 metres that spun around hitting the coast.