The Fast Break – Victoria

Seasonal climate risk information for Victoria

Volume 20 | Issue 1 | 21 January 2025

It’s been drier for the last 6 weeks in the west and finally some rainfall fell in the east. Soil moisture has remained unchanged in many paddocks, particularly the cropping ones where weed control has been enacted. The higher-rainfall perennial pastures experienced a delayed spring moisture drawdown, due to the late spring rain, but have used some significant soil water. Soil moisture in the south-west is very low.

The Pacific Ocean has made an attempt at coupling into a La Niña, but this appears short-lived. The central Pacific took a long time to cool close to a La Niña threshold and is forming a ‘modoki’-type pattern. A horseshoe of warmer water in the western Pacific is reminiscent of a La Niña-like sea surface temperature pattern. The ocean remains very cool in the eastern Pacific undersea. Trade winds have been stronger in the western Pacific, which has been holding and building a pool of warmer water to the north-east of Australia. Equatorial cloud patterns have been broadly keeping with a La Niña-like pattern. The tropical pressure briefly became interested, with lower pressure at Darwin and a strongly positive Southern Oscillation Index (SOI), but this has now collapsed back to neutrality. Most models predict this was the last showing for a La Niña, expecting a slow warming of the Pacific back to normality.

The Indian Ocean shows no Indian Ocean Dipole (IOD) activity, as is normal for summer. IOD events can only form as early as May, once the northern Australia wet season is over. Stronger westerly winds in the central Indian Ocean are possibly due to the presence of the Madden–Julian Oscillation (MJO) in that area. Stronger north-west winds feeding into north-west Australia are likely due to the formation of tropical cyclone ‘Sean’. Irrespective of the reasons, this wind activity is likely to push and hold warmer water to the north-west of Australia.

The seas to the north of Australia are warmer and better moisture sources, but as is often the case in summer, getting connections to that moisture isn’t always easy.

The Southern Annular Mode (SAM) is not very active, but if it was to go positive that could increase rainfall in eastern Victoria over summer.

The MJO has been in its dry phase situated out in the eastern Pacific and western Indian Ocean. It’s predicted to come into the zones north of Australia in early February. Once again though, a moisture source without a southern process to draw that moisture down doesn’t guarantee anything.

Pressure patterns have also been benign, with high pressure not dominating over Victoria. The average latitude of the highs has been slightly north of a usual summer position, which has meant the tropical moisture has been pushed further north.

My assessment of 12 climate models for Victoria is split between increased chances of being wetter and neutral (anything could happen). Temperatures are likely to be warmer for the next 3 months.

Soil moisture

Compared to 30 days earlier than 21 January 2025

The BoM Australian Water Outlook (AWO) deciles for perennial pasture are ranked normal in most of northern Victoria. The south-west, central and west Gippsland regions are ranked drier. Scrutinising the soil moisture probe values, since the storms of early summer there has been little change in the northern paddocks. On and south of the ranges, many perennial pasture paddocks have continued to use stored soil water. The Greta phalaris declined 48 percentage points from 100% to 52% and the Yarram perennial ryegrass decreased 28 points from 54% to 26%.

Soil moisture probe data can be accessed in real time at Agriculture Victoria’s soil moisture monitoring website.

Probes from Agriculture Victoria, Dookie Land Management Group, Gecko Clan, Perennial Pasture Systems, Gippsland Agriculture Group, Murrayville Landcare and Riverine Plains Inc. networks.

Predicted rainfall: February to April 2025

Predictions for February to April – the outlook from 12 global model forecasts is split between likely wetter and neutral across Victoria. There is a stronger consensus for a wetter eastern half of Victoria.

Predicted temperature: February to April 2025

Predictions for February to April – the outlook from 11 global model forecasts is for likely warmer across Victoria.

Model distribution summary for the next 4 to 6 months

Predicted rainfall: May to July 2025

Predictions for May to July – the outlook from 9 global model forecasts is neutral.

Predicted temperature: May to July 2025

Predictions for May to July – the outlook from 9 global model forecasts is for likely warmer across Victoria.

Model consensus forecast for the next 6 months

Current outlook (21 January)

Previous outlook (25 December 2024)

Sea surface temperature (SST) anomalies

During December and January the equatorial Pacific Ocean surface cooled. The oceanic values for NINO3 and NINO3.4 were −0.13 and −0.67^oC, respectively (21 January). NINO3.4 briefly got below the −0.8^oC threshold in January but this has been short-lived.

The cooling is very much centred in the Pacific in a ‘Modoki’ La Niña-like pattern. Most models predict this was the last hurrah for this attempted event and the Pacific Ocean will return to be slightly cool. The warm water in the Coral Sea appears in a La Niña-like formation and is an improved moisture source.

The Indian Ocean Dipole is currently neutral, as is normal over summer and the Dipole Mode Index reflects this currently at −0.24^oC (19 January). The very warm water off the WA coast is also a switched-on moisture source and recently spawned tropical cyclone ‘Sean’.

Sea surface temperatures are the key to the world’s rainfall. For more information on how they are measured, maps created and how to read them, check out our eLearn

National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch Daily 5 km SST Anomalies (Version 3.1) 19 January 2025.

Equatorial Pacific subsea temperature anomalies

Analysis done 20 January 2025

The Pacific Ocean Equatorial sub-surface temperature remains cooler at depth in a pre-Niña like state. Increased easterly trade winds have helped cooler water upwell and intensified the undersea cooling. A large warmer section of water has formed in the western Pacific under the warmer surface. It is too early to tell what the undersea will get up to in 2025. A pattern like this at this time of the year could turn into La Niña, neutral or El Niño.

Southern Oscillation Index (SOI)

30-day moving SOI: 18 January 2025

The SOI moved into La Niña-like values above +7 for much of December and early January, but has recently rapidly declined to normal levels. The SOI is currently at −0.7 (as of 18 January). Pressure was interested in La Niña, with lower pressure at Darwin and higher at Tahiti, but pressure has recently increased at Darwin.

© Copyright Commonwealth of Australia 2025. Bureau of Meteorology. Climatology period 1933–92.

Dipole Mode Index (DMI)

Latest weekly value to 19 January 2025

The DMI is the difference between the temperature of the west and east boxes of ocean monitored for the IOD. The IOD is currently neutral, as is normal in summer (currently −0.24^oC on 19 January).

© Copyright Commonwealth of Australia 2025. Bureau of Meteorology.

Pacific Ocean surface wind anomalies

Wind direction and strength anomalies for the last 30 days

Operational data: Surface winds (m/s) 30-day anomaly for Sunday 22 December 2024 to Monday 20 January 2025.

During December and early January easterly trade winds strengthened in the western Pacific, which moved the Pacific Ocean towards a weak but brief La Niña-like state. While stronger winds prevail, the warmer water to Australia’s north-east is likely to intensify and remain. Stronger westerly winds in the central Pacific are probably due to the positioning of the Madden–Julian Oscillation. Stronger north-west winds off Sumatra are most likely a result of tropical cyclone ‘Sean’. Both would be expected to increase the warmer water pool in the eastern Indian Ocean.

(NCEP Operational climatology data: 1985–96, smoothed with 5-day running mean.) Source: NOAA.

World cloudiness anomalies

OLR anomalies: Average of 19 December 2024 to 18 January 2025

Cloud at the junction of the Date Line is less than normal, which is like a La Niña, but the cloud signature to the north of Australia is not. Increased cloud in the Timor Sea is most likely due to tropical cyclone ‘Sean’.

Source: Bureau of Meteorology.

Southern Annular Mode (SAM)

AAO: Observed and GFS forecasts

29 September 2024 to 20 January 2025

The Southern Annular Mode (SAM) or Antarctic Oscillation (AAO) has spent the first half of December weak to moderately negative and since then has been bouncing between weakly positive and negative. A positive SAM in summer can lead to more moisture flow into the east of Victoria. In the next 14 days both BoM and NOAA predict a period of neutrality. Some models predict a wetter eastern half of Victoria in the next 3 months which has fingerprints of a positive SAM.

Source: NOAA.

Madden–Julian Oscillation (MJO)

MJO phase diagram for 10 December 2024 to 18 January 2025

In the last 30 days the MJO cloud band moved from the western Pacific across to the western Indian Ocean. Positions 5 and 6 are the more critical to Victoria as a moisture source being north-west and north-east of Australia, respectively. The passage of the MJO also kicks off bursts of the northern monsoon. The BoM ACCESS model predicts the MJO to get to positions 5 and 6 around early February with some strength.

Source: Bureau of Meterology.

Air pressure

Last 30 days air pressure

Sea level pressure (mb) 30-day mean for Sunday 22 December 2024 to Monday 20 January 2025.

In the past 30 days the Sub Tropical Ridge of High Pressure (STR) has been centred over Adelaide, a position further north of the normal summer position of Melbourne. Victoria has not been dominated by high pressure with relatively normal speed passage of the weather systems.

Source: NOAA.

Air pressure anomalies

Last 30 days air pressure anomaly

Sea level pressure (mb) 30-day anomaly for Sunday 22 December 2024 to Monday 20 January 2025.

The Sub Tropical Ridge was slightly lower in pressure over Victoria during January, but only eastern areas of the state have experienced tropical moisture flow. Pressure was slightly higher at Darwin and normal at Tahiti. This is why the SOI is only weakly positive and normal. A La Niña would normally have much lower pressure at Darwin.

(NCEP Operational climatology data: 1985–96, smoothed with 5-day running mean.) Source: NOAA.

Climate definitions

Read a list of climate acronyms and explanations.

Modelled climate and ocean predictions for Victoria from January 2025-run models

Twelve climate models show their predictions for the next 6 months for the Pacific Ocean, Indian Ocean, rainfall and temperature for Victoria.

View a colour-coded version of this table (WORD - 77.3 KB)

Our e-learning module How to read the Fast Break table explains this table.

Four coupled global circulation model forecasts

*FMA = February, March, April; MJJ = May, June, July; JJA = June, July , August

Four coupled global circulation model forecasts

*FMA = February, March, April; MJJ = May, June, July

Three ensembles and a statistical model forecast

Image references

Original images used in this document are sourced from the Bureau of Meteorology under a Creative Commons 3.0 licence and from the NOAA which has a public domain policy. Annotations highlighting areas of interest have been added by Dale Grey.