Tropical outlooks and monitoring

Unseasonable rainfall over parts of northern Australia

Unseasonable rainfall occurred over parts of northern Australia from 17 to 20 June due to a trough and associated cloudband. Most notable falls occurred in the 48 hours to 20 June with accumulated totals reaching 15–50 mm across eastern Northern Territory and western Queensland, and 10–25 mm in the far north of the Northern Territory. Several Top End sites observed record-high June daily rainfall, including:

• 14.0 mm at Humpty Doo Collard Road (20 June, 43 years of record).
• 13.4 mm at Wandie Creek (19 June, 28 years of record).

These rainfall totals are notable given the typically dry June conditions, with average June rainfall of less than 1 mm across the Top End. The system shifted eastward from 20 June, with a ridge bringing drier south-easterly flow.

Cloud cover, rainfall and cool southerly winds resulted in maximum and minimum temperatures up to 4 °C below average across much of north-western Australia over the past fortnight, with some sites recording their lowest June daytime temperature on record, including 23.0 °C at Middle Point (NT) on 19 June (25 years of record), which is the lowest on record for any month.

Long-range forecast

The long-range forecast for July to September, issued on 25 June, indicates above average rainfall is likely for parts of the far tropical north. This forecast falls within the northern Australian dry season, when most of the tropical north, except for the east coast of Cape York Peninsula, typically receives very little rainfall. Therefore, only small amounts of rainfall, often less than 20 mm, can be enough to exceed seasonal averages.

Maximum temperatures for July to September are likely to be below average (60 to 80% chance) across northern parts of Queensland and the Northern Territory, while minimum temperatures are likely to be above average for most of the tropical north except in parts of the NT's interior.

Madden-Julian Oscillation (MJO)

Over the previous fortnight, the Madden–Julian Oscillation (MJO) has weakened from a moderate to strong pulse in the Western Hemisphere and is now indiscernible as of 29 June. Most models forecast the MJO to redevelop over the Maritime Continent and propagate into the Western Pacific over the coming week.

Tropical low forecast near the Solomon Islands

A tropical low is forecast to develop north-east of the Solomon Islands this week, assessed as having a low chance (around 15%) of tropical cyclone (TC) development from Friday. The low is likely to bring heavy rainfall and strong winds to parts of the Solomon Islands and Papua New Guinea from Wednesday with possible localised flooding. No direct impacts are expected for Australia.

The last TC to form to the north-east of the Solomon Islands at any time of the year was Tropical Cyclone Raquel in June 2015.

For updates on tropical cyclone forecast, go to the Tropical cyclone forecast.

Indian monsoon onset

The Southwest Indian Monsoon arrived over Kerala on 4 June, around 3 days later than usual, and has continued to progress northwards. As of 29 June, the monsoon has arrived in southern Gujarat and Madhya Pradesh, northern Chhattisgarh, and western Jharkhand and Bihar, remaining behind its climatological position. For updates on India's Southwest Monsoon onset, go to the Monsoon Information Onset | India Meteorological Department.