... as the floodgates of the sky get ready to be opened. Forecast rainfall of about 150mm to 300mm over central parts of the Top End and the far North Kimberley are on the cards for this Christmas period. After weeks of increasing humidity and temperatures since the beginning of the wet season in October, the North Australian Monsoon (NAM) will finally bring a relief to this heat. Many Territorians do go troppo over the so called "build up", the period when temperature and humidity levels begins to increase in late September but with little rainfall to alleviate the mugginess. Although there are a few definitions for the monsoon, the most common terminology applies to the reversal of the wind direction. In northern Australia, south easterly trade winds characterise the period from April to September also known as the Dry Season. During the Wet Season (October to May), these winds revers the direction to a more north westerly flow, bringing the heavy monsoonal rains. During the monsoon season, there are usually a few active phases of the monsoon which bring heavy rainfall to northern Australia. These occur when the monsoon trough moves south over the Australian landmass. To its north, moisture laden north-westerly winds while to its south the south-easterly winds will be cooler and drier. The trough may stay over land for periods varying from days to weeks, bringing an active phase. When the monsoon retreats to the north of Australia (i.e. over Indonesia), dry south-easterly winds will spread over much of the tropical north, bringing break in the monsoon. A broad trough over central Australia is likely to bring monsoon-like conditions to the Northern Territory and far north WA during the next four days, with heavy rains and thunderstorms contracting north after boxing day.