Climate Outlook - Barkly Tableland (June - August)

June, July, August climate summary

• The chance of exceeding median rainfall is only about 20-25%.
• Maximum and minimum temperatures are very likely to be above average.
• The El Niño forecast has been downgraded to El Niño Watch, with most models predicting a return to neutral conditions by the middle of the dry season.
• The IOD exceeded positive thresholds at the end of May. To be a positive IOD event, thresholds need to be sustained for at least two months. A positive IOD means reduced likelihood of rainfall through central and southern Australia in winter (the Barkly is really on the edge of this).

Climate workshops

In April this year, the NACP climate scientists, BOM scientists and Anne Marie Huey (Climate Mate for the East Kimberley and VRD) held climate workshops in Kununurra and Katherine. Here is some of the feedback from pastoralists who attended:

“It improved my knowledge of interpreting data on the BoM website.” “It helps me a lot to make climate related decisions at the field level.”

“More positive outlook on understanding tools that can be used with assistance to understand climate risk.”

“Highly recommend to other pastoralists.”

Climate Workshops with Bureau of Meteorology and University of Southern Queensland climatologists will be held on the Barkly in August this year. To register your interest, please email Alison.kain@usq.edu.au or phone 0409 281 649.

Barkly climate outlooks

Hopefully you have all been receiving the monthly Barkly Climate Outlooks and Supplements. I have received some positive feedback but the thing about these projects is that we need to be able to show those who are funding them that they are useful. Please let me know by emailing Alison.kain@usq.edu.au whether you would like to keep receiving these, whether your preference is a paper copy or whether you are no longer interested in receiving them.

This month's featured climate driver

The Indian Ocean Dipole

(to refer to figures and images of the following explanation, please download the PDF version of Barkly Beef PDF (3.1 MB))

The IOD is a measure of Sea Surface Temperatures in the western and eastern Indian Ocean. Warm water flows through the islands of Indonesia to the region north west of Australia.  When the IOD is neutral, warm air rises in the region north west of Australia and circulates over to the western Indian Ocean. Westerly winds blow across the equator, thus maintaining the cycle of convection.

When the IOD is positive, the westerly winds decline and the ocean in the western Indian Ocean becomes increasingly warm resulting in a cooler eastern ocean temperatures. Cool oceans mean less convection and less moisture available for rain.

In a negative IOD, the westerly winds become stronger leading to warmer than average ocean temperatures near Australia and an increase in moisture available to weather systems crossing the country.

Big climate drivers like the IOD don’t necessarily alter the weather patterns that move across Australia however they can play an important role in the moisture available to the local weather patterns and the subsequent rainfall potential.

What does it mean for rain forecasts?

The IOD exceeded positive thresholds at the end of May 2019. To be a positive IOD event, thresholds need to be sustained for at least two months. A positive IOD means reduced likelihood of rainfall through central and southern Australia from winter to spring. While the Barkly is a bit to the north of that region, historically, the winter-spring (June to November) period is often drier in an IOD positive year.

What does it mean for the Barkly?

It’s important to note that the IOD breaks down around November/December with the onset of the northern wet season. While it doesn’t have an impact on the subsequent wet season, it can influence the likelihood of early rainfall around October and November.

Contact

For more information, please contact Alison Kain on 0409 281 649, alison.kain@usq.edu.au