The Department of Environment and Science (DES) monitors sea-surface temperature (SST) anomalies in key regions of the Pacific Ocean over autumn, winter and spring, and provides objective outlooks for summer (November to March) rainfall on this basis. Based on the SST pattern in the Pacific Ocean leading up to summer, the Science and Technology Division of DES considered that the probability of exceeding median summer (November to March) rainfall was higher than normal across Queensland (see map in PDF).
The most closely monitored driver of Queensland rainfall is the El Niño-Southern Oscillation (ENSO) phenomenon. This coupled ocean-atmosphere pattern tends to build over winter and spring and then persist through summer, favouring above-average summer rainfall in Queensland. Climate scientists monitor several ENSO indices, including the atmospheric Southern Oscillation Index (SOI) and SST anomalies in the Niño 3.4 region of the central equatorial Pacific Ocean. Indicative of the current ‘La Niña’ climate pattern, the SOI has remained quite positive (average +10.1) over the last three months (October to December) and the SST anomaly in the Niño 3.4 region has been much cooler than average (-1.3°C).
December rainfall was well-above average across much of northern Queensland (see map in PDF) and the northern Australian monsoon has remained quite active. On January 3, Tropical Cyclone Imogen made landfall near Karumba, leading to widespread rainfall across northern Queensland. At present (January 18), Tropical Cyclone Kimi is tracking toward Cardwell and is likely to bring further high rainfall to the tropical north.
Readers are cautioned that seasonal outlooks are expressed in terms of probabilities. Even though an outcome has a high probability of occurring based on historical records, a less likely outcome may still occur in any given year.
For more information, please contact Ken Day: firstname.lastname@example.org