Seasonal Climate Outlook

Recent climate

November rainfall was below average to average for the SWLD. Year to date decile rainfall map indicates decile 1-3 rainfall for the SWLD.November maximum temperatures were above average and minimum temperatures were average to above average. The number of days above 30˚C in the SLWD in November were high.

Rainfall decile map 1 January to 2 December 2019 for the South West Land Division.

Number of days over 30˚C in November in the South West Land Division.

In November, the atmospheric pressure was above normal over the SWLD.

Indian Ocean sea surface temperatures (SST)  off the WA coastline have been cooler than average. The December 2019 to February 2020, SST forecast by the Bureau of Meteorology indicates SSTs are likely to be warming up north of WA.

The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere.  SAM has been negative since July and is forecast to remain negative until at least late December.  A negative SAM increases the chance of spring heatwaves occurring across southern Australia.

The strong positive Indian Ocean Dipole (IOD) continues to influence Australia's weather, but has weakened over the past four weeks. The IOD continues to show signs it will persisted later than usual this year, and will dissipate when the monsoon trough moves into the southern hemisphere, in mid-December. The El Niño–Southern Oscillation (ENSO) is expected to remain neutral for the remainder of 2019. For further information, see the Bureau of Meteorology’s ENSO Wrap Up.

The table below gives a summary of past month and three-month South West Land Division (SWLD) climate conditions, and can indicate what is likely to occur in the near future if climate conditions follow the current pattern.