The likely last monsoon trough for the season should move over far northern Australia late this week, bringing widespread rain and storms and an increased chance of tropical cyclones.

It's hardly been dry over many tropical areas in recent weeks, most notably the Kimberley and northeast Queensland around Cairns, but this stormy rain has been caused by weather patterns other than the monsoon.  

For the Kimberley, it was a long-lasting low pressure trough that extended all the way to NSW at times; parts of the Kimberley saw totals between mid-March and last weekend to rival those of eastern NSW over the same period. For Queensland, it has been persistent onshore winds, driving moisture up and over the Tablelands, that forms cloud that then drops rain. 

While storms and rain can and do develop during monsoon 'break periods', an 'active period', like expected this week, is characterised by deep northwesterly winds over a wide area that drag moisture southwards from the equator. This moisture is then deposited as widespread rain. 

Image: Winds converging into the monsoon trough north of Australia on Saturday 3rd April, according to the ECMWF model. 

The proximity of the monsoon trough's circulating winds and enhanced instability also hugely increases the chance of tropical cyclone development.  

A monsoon trough is expected to be near the northern Australian coast from Friday or Saturday this week and the most likely area to be affected by this particular monsoon period is the Top End of the Northern Territory. Indications of a tropical Cyclone near the Top End over the Easter weekend are increasing.  

Some areas of the Top End are likely to pick up three figure rainfall totals to cap off a wet season that already ranks in the wettest 10% of all recorded seasons.