When humidity starts to rise and the fish start to bite in the Northern Territory, the locals know the Build-Up is here. From October, as the monsoon season is approaching, humidity in the Top End begins to increase. As a result, thunderstorm activity is also on the rise. Constantly forming heat troughs and short-lived localised low pressure systems become a regular feature in the north, delivering rain and storms to a landscape shaking off the dust from the dry season. Each night this coming week will see a chance of storms forming along the north coast. The Build-Up, however, is not just about the atmosphere. It's also a great time of the year for fishing. Barramundi are at their most active with populations increasing in estuaries and rivers preparing to spawn. Many other species like Saratoga are also active, meaning fisherman can't flick their lures out quick enough. Across the next month or two there is an increased risk of lower than average rainfall for the NT Top End. This is due to an El Nino event in the Pacific and the development of a positive phase in of the Indian Ocean Dipole (IOD), which both reinforce a drier than usual pattern in the north. However warmer than usual waters across the eastern Indian Ocean should moderate their influence, bringing the chance of wetter conditions, particularly as we look towards the end of the year. No matter how much it rains in the next few months, you can always cast away your worries and throw out a line somewhere in the Top End.