Recent climate
Rainfall in February was second wettest for the South-West Land Division and also the second wettest summer behind 1955. Thunderstorms on 2 March, lead to wide spread rainfall throughout the wheatbelt with 39mm recorded in Tardun Rock and 13mm in Wongan Hills. Further thunderstorms on 12-13 March led to weekly rainfall totals of 58mm for Ardath in the central wheatbelt. Check DAFWA soil water tool for modelled stored soil moisture estimates.
February South-West Land Division maximum temperatures were 1.6°C below average, and lowest since 2001, whilst minimum temperatures were near average.
The El Niño–Southern Oscillation (ENSO) remains neutral, but the Pacific Ocean is warming. Six out of eight models are suggesting an El Niño to develop by July. The Bureau is currently on an El Niño watch.
Indian Ocean sea surface temperatures (SSTs) north of Australia have warmed in the past week and now are slightly above average. The Madden Julian Oscillation is in an active phase but is beginning to weaken as it approaches northern Australia. Surprisingly, there has only been one tropical cyclone cross the Australian coast this season, Blanche on 6 March, despite expectations of an average to above average tropical cyclone season. However, numerous tropical lows and thunderstorms have had an impact on the climate of WA over the past months, bringing record rainfall to the Kimberley, as well as the southwest. Although the continuation of this activity appears unlikely as the MJO weakens, tropical activity in March and April can lead to more rainfall for the northern and eastern wheatbelt if lows move through the region (Olwyn in March 2015 and Elaine in March 1999). For a summary of Pacific and Indian Ocean outlooks, see the Climate Model Summary produced by the Bureau.
The influence of the Indian Ocean Dipole (IOD) on Australian climate is weak during December to April. This is due to the monsoon trough shifting south over the tropical Indian Ocean and changing the overall wind circulation, which in turn prevents an IOD ocean temperature pattern from being able to form. Current outlooks suggest a neutral IOD for the end of autumn.
The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere. SAM is currently near zero and is expected to remain so up to end of March. The negative SAM in summer was partly responsible for the out of season cold fronts and cooler conditions.
In February the atmospheric pressure was above normal over the southwest. These higher than normal pressures over western and southern Australia are forecast to continue, meaning fewer cold fronts are likely to cross the coast.
The table below gives a summary of past month and three month southwest Western Australia (SWWA) climate conditions, and can be used as an indication of what is likely to occur in the near future, if climate conditions follow the current pattern.
| Climate indicator | Past month | Past three months |
|---|---|---|
| SWWA rainfall | Very much above average | Very much above average |
| SWWA mean temperature | Below average | Below average |
| SWWA atmospheric pressure | Higher | Normal |
| Indian Ocean sea surface temperature | Cooler | Cooler |
| El Nino/Southern Oscillation (ENSO) | Neutral | Neutral |
| Indian Ocean Dipole (IOD) | Neutral | Neutral |
| Southern Annular Mode (SAM) | Neutral | Negative |