Forecast

Issue Notes

The hemispheric long wave pattern has remained stable in recent weeks. There are five main troughs. Currently the most significant troughs are near the longitudes of the southwest Indian Ocean, Western Australia, eastern Australia, the south Pacific, and the Atlantic Ocean.

Summary:

Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 26 July to 30 July, 10 August to 14 August, and 18 August to 22 August. Rain events originating in the tropics and moving south are possible about 15 August to 19 August. Over Western Australia the strongest cold fronts should occur about 6 August to 10 August, 11 August to 15 August, and 15 August to 19 August.

Issue Notes - Issued Jul 10

ENSO status: Neutral Sea surface temperatures (SSTs) showed a cooling trend over the central Pacific during June, though remain on the warmer side of neutral across the equatorial Pacific. The Nino3.4 index lingered between 0.6 and 0.5 through the month of June.The Southern Oscillation Index (SOI) recorded a value of -10.4 in June, remaining within El Nino territory. Current consensus suggests warmer than average SSTs will remain across the equatorial Pacific Ocean through the remainder of winter. Moreover, seven out of eight international models maintain a warmer than average Pacific Ocean through the remainder of 2019, with a 50-60% chance of an El Nino developing again later this year. The climate outlook for winter and early spring continues to favour an average-to-below average rainfall outlook across the southern half of Australia. A Positive IOD is now established over the Indian Ocean, with five out of six international models exhibiting a moderate-to-strong event lasting until late spring. During Positive IODs, central and southeastern Australia tend to see a reduction in rainfall during the second half of winter and the first half of spring. SSTs along the eastern seaboard remain significantly warmer than average, maintaining a high risk of extreme weather events such as East Coast Lows (ECLs). These can bring intense periods of rainfall east of the Great Dividing Range, leading to flash flooding.