Climate outlook for October to January
Climate outlook overview
- Rainfall is likely to be below average across most of the country, excluding northern WA, for the remainder of 2019 with high chances of a drier October and November in particular.
- Daytime temperatures are very likely to be above average across Australia for all outlook periods, with a spell of hot weather likely in early October.
- Nights are likely to be cooler than average in the NT's Top End during October, but elsewhere generally warmer than average.
- A positive Indian Ocean Dipole (IOD) is likely to remain the dominant climate driver for Australia until at least the end of spring.
- A prolonged period of negative SAM (Southern Annular Mode) may also contribute to the dry/warm outlooks for eastern Australia during October and November.
Drier than average likely, but may start to ease in summer
- Rainfall for the remainder of 2019 (October to December) is likely to be below average across much of Australia, with high chances of a drier October and November in particular.
- The dry signal is likely to ease in northern WA from November, with the November to January period showing neutral to above average chances of exceeding median rainfall in this region.
- The short-term outlook suggests some rainfall is likely in the second week of October for parts of northeast NSW and far southeast Queensland.
Above average temperatures set to continue
- Daytime temperatures are very likely to be warmer than average across the Australia mainland for the remainder of 2019 and early 2020.
- A spell of warmer weather is likely during early October, with weekly temperatures expected to exceed more than two degrees above average across much of the country, particularly in inland areas.
- Nights are likely to be cooler than average in the Top End during October, but warmer than average elsewhere.
- For the three-month periods of October to December and November to January, there are strong chances of warmer than average nights for the majority of the country, but the odds ease to 50:50 in the southeast and on the Queensland coast.
- The positive Indian Ocean Dipole (IOD) has strengthened in recent weeks and is forecast to continue until at least the end of spring. Typically, this means below average rainfall for much of central and southern Australia during spring, and warmer than average temperatures; consistent with the current outlook.
- IOD events typically have little influence on Australian climate from December to April, meaning its contribution to the drier outlook should start to reduce in early summer.
- A prolonged negative phase of the Southern Annular Mode (SAM) is expected to persist during October and November. A negative SAM in spring tends to bring drier conditions to parts of eastern Australia. It also doubles the chance of spring heatwaves occurring across southern and eastern Australia.
- Forecast warmer than average sea surface temperatures off the northern WA coast are likely contributing towards the increased chances of above average rainfall for northern WA in October to December. Similarly, cooler than average waters are forecast further east, over northern Australia. These cooler waters are likely contributing towards the drier forecast across much of this region for October to December, as well as the cooler nights.
- The El Niño–Southern Oscillation (ENSO) is expected to remain neutral until at least early 2020.
- In addition to the natural drivers such as ENSO and the IOD, Australian climate patterns are being influenced by the long-term increasing trend in global air and ocean temperatures.
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