THE CLIMATE KELPIE BLOG: What’s predicted in October?

Posted by BCG on 3rd October 2019

The positive Indian Ocean Dipole (IOD) will remain as the dominant climate driver for the rest of 2019. In addition, a negative phase of the Southern Annular Mode (SAM) is forecast to continue bringing with it drier and warmer air from inland Australia across to the eastern states via more westerly winds. The outlook, therefore for the remainder of 2019 and into early 2020 is for likely for hotter and drier conditions for most of Australia.

Rainfall Roundup

In September, large parts of Australia remained very dry except for some areas around our capital cities where near “Average” rainfall was recorded (Fig. 1). Parts of the NT and WA were fortunate enough to receive “Above Average” rainfall for September but when put into context, these rainfall events were no greater than 20mm. The generally dry conditions of September have contributed greatly to the “Below Average” to “Very Much Below Average” rainfall conditions across Australia for the last 3 months with several places in the Murray Darling Basin, SA and WA recording the “Lowest on Record” (Fig. 2).

Figure 1. Rainfall deciles for September 2019.
Figure 2. Rainfall deciles for July to September 2019.

Rainfall Forecast

The BoM’s ACCESS model suggests ‘Very Much Below Average’ rainfall is likely over the last 3 months of 2019 for large parts of Australia including much of eastern, central and northern Australia (Fig. 3). However, for northwest WA, “Above Average” rainfall is likely for this period and the outlook for the northern rainfall season suggests that the first rains are likely to arrive later than usual (Fig. 3).

At this time of year accuracy for the three-month forecast is moderate, except for parts of WA and NT which are low and parts of the eastern states with are high.  

Figure 3. Australian outlook for October to December 2019.

Temperature Roundup

In September, maximum temperatures were “Above Average”, across much of Australia, particularly in parts of WA (Fig. 4). However, parts of Victoria, QLD and NT recorded “Average” maximum temperatures.

Minimum temperatures were “Below Average” across northern Australia and the east coast however pockets of NSW, TAS, SA and the much of WA were “Above Average” (Fig. 5).

Figure 4. Maximum temperature deciles for September 2019.
Figure 5. Minimum temperature deciles for September 2019.

Temperature Forecast

The BoM’s ACCESS model forecast suggests ‘Above Average’ maximum temperatures are likely across most of Australia over the next three months (Fig. 6).  

Minimum temperatures are likely to be “Below Average” in parts of the southeast and tropical north during October, however there is a very high chance that nights will be “Above Average” over most of WA and increased chances for northeast NSW and southeast Queensland (Fig. 7).

At this time of year accuracy for the three-month forecast is moderate to high for the maximum temperatures and moderate across most of Australia for the minimum temperatures (except for parts of QLD, NT and WA).  

Figure 6. October to December maximum temperature outlook.
Figure 7. October to December minimum temperature outlook.

Climate and Water Outlook Videos

The Bureau of Meteorology releases regular outlook videos, covering all this information. Watch the most recent video below.