Forecast

Issue Notes

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

Summary:

Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 15 February to 19 February, 22 February to 26 February, and 29 February to 4 March. Rain events originating in the tropics and moving south are possible about 2 February to 6 February, 9 February to 13 February, and 22 February to 26 February. Over Western Australia the strongest cold fronts should occur about 7 February to 11 February, 15 February to 19 February, and 29 February to 4 March.

Issue Notes - Issued Jan 14

ENSO status: Neutral IOD status: Neutral SAM status: Trending neutral Sea surface temperatures (SSTs) across the equatorial central Pacific remained stable throughout December with the Nino3.4 index registering a value of 0.4 throughout the month. On the other hand, the Southern Oscillation Index (SOI) recorded a value of -5.5 in December. The current outlook suggests warmer than average SSTs will persist across the equatorial Pacific Ocean through the coming months, but remaining within neutral values. Six out of eight international models maintain a warmer than average equatorial Pacific Ocean through the first two quarters of 2020, none of these reaching El Nino thresholds. To the west of Australia, the Indian Ocean Dipole (IOD) has now returned to neutral, as waters off Western Australia have warmed up considerably. All six international models maintain neutral values until the austral winter with indications we could see another positive event later this year. In terms of rainfall across Australia, the current outlook favours a clearer below average rainfall signal for Western Australia and the Northern Territory through the remainder of January. This however, excludes any extreme weather events such as tropical cyclones. For the eastern states, there is a wetter than average signal for the coming weeks. Looking further ahead, with no significant signature from ENSO, there are no significant climate drivers tilting the balance towards a drier or wetter February. The current outlook suggests average-to-below average odds for February and March across the eastern states. The northern and western half of the country, however, could see a wet end to summer/start to autumn.