Fast Break: Climate risk information for South Australia
Author: Dale Grey, Department of Economic Development, Jobs, Transport and Resources | Date: 04 Jul 2018
Volume 1 | Issue 3
Most northern agricultural areas could do with more soil moisture, with only the SE region being closer to normal.
Things are delicately poised at the moment. The Pacific Ocean surface is slowly warming but still at neutral values. The undersea is much warmer in the eastern Pacific, which is where many models are getting their predictions for a winter or spring forming El Niño. Despite the undersea primed for El Niño, all other indicators such as, trade winds, SOI and Pacific surface temperatures are still at neutral levels. Indicators like the cloud at the dateline have quite a way to move as they are still more like La Niña.
These things suggest that if an El Niño is to occur, it’s still some time off. It’s important to remember that El Niño doesn’t guarantee drought in SA. Historically El Niño years have resulted in South Australian spring rainfall being in the lowest third around 50-60 per cent of the time. Most of these drier years can still be agronomically OK, but soil moisture reserves play a big role. Low rainfall drought years have occurred less than 10 per cent of the time.
The SAM is still behaving normally and the latitude of the Sub Tropical Ridge of high pressure is good. Unfortunately like in May, the pressure has situated itself over SA which means all but the most coastal and higher altitude regions have been in a blocked pattern. Absolute pressure is still higher, meaning highs are moving slower and pushing rainfall triggers south. Higher pressure at Darwin is making moisture harder to transport south.
More model predictions are leaning towards a spring forming El Niño, but trade wind reversals near PNG need to occur to lock this in. Predictions for the Indian Ocean over winter are all over the shop, anything could happen. Most model’s rainfall and temperature predictions are still sitting on the fence for average, code for anything is possible.
Model distribution summary for the next three months
Model distribution summary for the next four to six months
Model consensus forecast for the next six months
Current outlook (28 June)
Current outlook (28 May)
Neutral (possible El Niño)
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