Tropical Climate Update

Heavy rainfall for parts of Queensland

From 2 April, an inland trough across Queensland's interior interacted with tropical moisture from the Northern Territory tropics to bring heavy rainfall to parts of tropical Queensland. Later in the week, rainfall contracted to the state's far north, due to drier air being advected from the south. 

For the week ending 7 April, rainfall totals in parts of Queensland's interior and coast exceeded 100 mm, while areas of the Gulf Country and Central Highlands and Coalfields districts recorded more than 200 mm. Some stations had their record highest daily rainfall for April, including Tambo Post Office (149 years of data) which recorded 161.5 mm in the 24 hours to 9 am on 2 April. The highest weekly total (at a Bureau gauge) to 9 am on 7 April was 280.0 mm at Yappar River station in the Gulf Country.

Parts of the Cape York Peninsula and the north of the Northern Territory recorded 50 to 100 mm for the week ending 7 April. Other parts of tropical Australia recorded little rainfall during the week.

Fortnightly forecast

April is typically a transitional month, with conditions typical of the dry season pushing into the tropics periodically as the sub-tropical high pressure ridge gradually moves northwards.

Forecast for the fortnight beginning 12 April, issued on 7 April, indicates that rainfall is likely to be below average for most of Western Australia, the Northern Territory and western Queensland, with above average rainfall likely only for the far northern part of Queensland's Cape York Peninsula. Maximum temperatures are likely to be below or near average for most of the tropical north, but above average for Queensland's east coast and parts of the Pilbara, Gascoyne and Southern Interior districts of Western Australia. Minimum temperatures are likely to be below average for most of the Northern Territory, Western Australia's Kimberley and parts of western Queensland and above average for most of the Cape York Peninsula and eastern Queensland.

Tropical Low (29U)

A tropical low (29U) is likely to form by 9 April in the Arafura Sea, assisted by an Equatorial Rossby wave. It is forecast to move in a westerly direction while remaining north of the Australian coast. Environmental conditions are favourable for development of 29U and from 11 April there is a moderate chance that it could develop into a tropical cyclone, most likely over waters north of Western Australia's Kimberley coast.

For the latest information see the Bureau's 7-day tropical cyclone forecast.

Madden–Julian Oscillation moving to the Western Hemisphere and Africa

During the past week to 5 April, a weak to indiscernible Madden-Jullian Oscillation (MJO) pulse was located over the Western Pacific region.

Forecasts for the MJO are mixed. However, some models indicate that over the next fortnight a weak signal of the MJO is likely to strengthen over the Western Pacific region and progress to the Western Hemisphere and Africa region at a moderate strength. The MJO is expected weaken or become indiscernible towards the end of April. When the MJO is in the African region, it is typically associated with the suppression of cloudiness and rainfall over northern Australia.

In the shorter term, an Equatorial Rossby wave is expected to enhance tropical activity in the Australian region until mid-April.