Recent research by Hendon et al, (2014) at the Centre for Australian Weather and Climate Research found the Southern Annular Mode to be the leading mode of circulation variability through parts of inland eastern Australia where cotton is grown; particularly in the spring planting period.
 
A positive SAM has been proven to increase moisture supply into fronts and troughs forming in eastern Australia. The chart provided by Climate Prediction Center (US) shows the most recent observations of the SAM or (AAO). 

A negative SAM traditionally leads to a dry westerly circulation pattern through eastern Australian cropping areas.
 
BOM researchers Lim and Hendon (2013) found the SAM has the strongest connection with El-Niño Southern Oscillation in October and November – whereby the SAM is influenced most by El Niño or La Niña conditions.

Growers and advisors are encouraged to monitor the phases of the SAM together with seasonal forecasting, multi-week and short term weather models during planting. A short cartoon explaining the SAM can be found HERE. 

The SAM has had a burst of exuberance into positive phase in early October and has not settled there as predicted, rather is tracking along in neutral. While 2010 has become a legendary benchmark La Niña year, it must be remembered that a record positive SAM has been found to be a large contributor to onshore flow and increased rainfall in that year (Lim et. al. 2016).

Antarctic Oscillation or SAM observations below (23 Oct)