Madden-Julian Oscillation (MJO)

The Madden-Julian Oscillation (MJO) is the major fluctuation in tropical weather on weekly to monthly timescales. The MJO can be characterised as an eastward moving 'pulse' of cloud and rainfall near the equator that typically recurs every 30 to 60 days.


MJO location and strength

These graphs show the strength and progression of the MJO through 8 different areas along the equator around the globe.
Area 3 is north west of Australia, 4 and 5 are to the north (the Maritime Continent), and 6 is to the north east.

RMM1 and RMM2 are mathematical methods that combine cloud amount and winds at upper and lower levels of the atmosphere to provide a measure of the strength and location of the MJO. When this index is within the centre circle the MJO is considered weak. Outside of this circle the index is stronger and will usually move in an anti-clockwise direction as the MJO moves from west to east.

MJO phase diagram
MJO phase diagram

*Note: There are missing satellite observations from 16/3/1978 to 31/12/1978 and a change to RMM methods in 2014.

Average weekly rainfall probabilities

These maps show average weekly rainfall probabilities for each of the 8 MJO phases. Green shades indicate higher than normal expected rainfall, while brown shades indicates lower than normal expected rainfall.

Select the 'Wind' checkbox to also show the expected 850 hPa (approximately 1.5 km above sea level) wind anomalies. The direction and length of the arrows indicate the direction and strength of the wind anomaly. The darker the arrow, the more reliable the information is.

The relationship of the MJO with global weather patterns changes with the season.
Read more: The Combined Influence of the Madden–Julian Oscillation and El Niño–Southern Oscillation on Australian Rainfall.

Maps of total and anomaly outgoing longwave radiation (OLR)

Global maps of outgoing longwave radiation (OLR)

Global maps of outgoing longwave radiation (OLR) highlight regions experiencing more or less cloudiness. The top panel is the total OLR in Watts per square metre (W/m²) and the bottom panel is the anomaly (current minus the 1979-1998 climate average), in W/m². In the bottom panel, negative values (blue shading) represent above normal cloudiness while positive values (brown shading) represent below normal cloudiness.

Tap boxes to view a timeseries graph of cloudiness for that region
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OLR totals over the dateline

OLR totals over the dateline (area at far right in region map above)

Regional maps of outgoing longwave radiation (OLR)

The graphs linked to this map show the OLRs for the different regions within the Darwin RSMC area. The horizontal dashed line represents what is normal for that time of year (based on the 1979 to 1998 period). The coloured curve is the 3-day moving average OLR in W/m². Below normal OLR indicates cloudier than normal conditions in this particular area, and is shown in blue shading. Above normal OLR indicates less cloudy conditions and is shown in yellow shading.

Time longitude plots

Time longitude plots of daily averaged OLR anomalies (left) and 850 hPa (approximately 1.5 km above sea level) westerly wind anomalies (right) are useful for indicating the movement of the MJO.

How to read the Time longitude plots

The vertical axis represents time with the most distant past on the top and becoming more recent as you move down the chart. The Horizontal axis represents longitude.

Eastward movement of a strong MJO event would be seen as a diagonal line of violet (downward from left to right) in the OLR diagram, and a corresponding diagonal line of purple in the wind diagram. These diagonal lines would most likely fall between 60°E and 150°E and they would be repeated nearly every 1 to 2 months.

Daily averaged OLR anomalies

Daily averaged OLR anomalies

Westerly wind anomalies

Westerly wind anomalies

Tropical Cyclone Lincoln crossed the Northern Territory coast

Tropical low 07U developed into Tropical Cyclone Lincoln in the southern Gulf of Carpentaria on the morning of 16 February. Tropical Cyclone Lincoln tracked south and soon crossed the remote Northern Territory coast between Port McArthur and the Queensland border in the afternoon of the same day. 

Tropical Cyclone Lincoln was soon downgraded to a tropical low and continued to move west across the inland Carpentaria, Barkly and Gregory and northern Tanami Districts of the Northern Territory to the Kimberley of Western Australia on 20 February.  

Tropical Cyclone Lincoln brought heavy daily rainfall of 100 mm to 200 mm in the Northern Territory and the Gulf Country of Queensland. Groote Eylandt Airport in the Gulf of Carpentaria recorded a daily total of 119 mm on the 15th, a February record at the site. Centre Island off the Carpentaria coast in the Northern Territory recorded a wind gust of 85 km/h (43 knots) on the 16th and 326.8 mm for the 2 days ending the 17th.  Sweers Island in Queensland recorded 227 mm on the 17th, also a February daily rainfall record at the site. Tennant Creek and Rabbit Flat recorded daily rainfall of 138.4 mm (to 9 am on the 18th) and 109 mm to 9 am on the 19th) respectively. As of 20 February, flood watches have been issued at multiple rivers catchments in the Northern Territory and Queensland's Gulf Country. 

 Ex-Tropical Cyclone Lincoln is forecast to move to waters west of the Kimberley and there is high chance (55%) it could redevelop to cyclone intensity on 22 February. The reformed cyclone likely tracks south-west towards the west Pilbara coast on weekend.  

Tropical Cyclone Lincoln is the fourth Tropical Cyclone of the 2023-24 season, and it is the first time that a Tropical Cyclone formed in the Gulf of the Carpentaria since Tropical Cyclone Alfred in February 2017. 

 

For more information on the ex-Tropical Cyclone Lincoln (07U) forecast, visit here.

For more information on flood watch and warnings, visit here.

Monsoonal rain lifted wet season rainfall totals to average in the Top End of the Northern Territory

Monsoonal flow brought widespread thunderstorms and frequent showers to the Top End of the Northern Territory in the past nine days (10-18 February), with 9-day rainfall totals recorded in the 100 mm to 300 mm range.  

Darwin Airport recorded a 9-day total of 357.6 mm, which is close to its February average of 370 mm. For the Wet Season to date (1 October 2023 to 20 February 2024), Darwin Airport recorded 1206.2 mm in total, which is close to its long-term average of October-February rainfall. 

Madden–Julian Oscillation has weakened

The Madden–Julian Oscillation (MJO) has weakened significantly in the central Pacific Ocean in the past week and is now weak or indiscernible. All international climate models indicate the MJO will remain weak in the coming week, with some models suggesting a strengthening in Maritime Continent at the start of March.

Product code: IDCKGEW000

ACKNOWLEDGEMENT: Interpolated OLR data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA.

Product Code: IDCKGEM000

Climate