It looks like we have some great late winter weather coming up for the Riversounds festival this weekend – and then through into next week as well! Great news for everyone looking to plant or dance.

Looking further ahead and we are once again on La Nina alert…though this is likely to be the last one. Here’s how it is looking under the Pacific right now – you can see the developing cold pool now reaching for the surface:

The cold pool is a result of a very strong trade wind burst that has been taking place over the last couple of months – more on that below. It is going to quickly strengthen the La Nina and result in a chance of significantly wetter than average conditions once again across our region. The latest model ensembles are in and this animation covers the next 9 months in three month intervals:

You can see the higher than average precipitation drop off as we head into next year. This is because the models are forecasting a weakening of the La Nina as we head into next Autumn. You can see this in the latest model ensemble run. Here’s how the Pacific looks right now:

…and here is the forecast for next April. You can see the weakening of the cold pool – and perhaps the development of a warm tongue in the far East as well – signs of a potential El Nino?

All of that is a long way into the future…for now we have a strong negative Indian Ocean Dipole and a developing La Nina. We’ve also got another stronger than average trade wind burst heading across the Pacific:

This one is further east, which increases the risk of the easterly burst making it onto the Australian East coast. Needless to say this would increase the risk of wetter weather over the coming weeks. Of note in the image above is also the trade wind burst from 20th June through 18th July – this is the burst that helped develop the new cold pool and renew the La Nina.

We’ve also got the Antarctic Oscillation also forecast to turn positive…which would also increase the chances of onshore winds and increased rainfall:

No real signs in the models yet of wetter weather, but if you recall a few months back we had a similar situation which did eventually lead to much wetter conditions. No guarantees of a repeat, just something to keep an eye on. One BIG weather event that did take place this year (that we have not yet discussed) was the Tonga volcanic eruption. The violent eruption injected an unprecedented amount of water directly into the stratosphere — and the vapour will stay there for years, likely affecting the Earth’s climate patterns. The water vapour may temporarily warm the climate and deplete stratospheric ozone…but exactly how that will play out over the coming few years is not yet clear. As scientists gather more information I’ll post the relevant information on this blog.

Thanks to our sponsors Kombu Wholefoods and Snapfrozen

Thanks to the following for images: Ben Noll Weather / NOAA / NCICS