The Department of Science, Information Technology and Innovation (DSITI) provides seasonal outlooks for the Queensland summer (November to March) from April to November each year. DSITI monitors sea-surface temperature (SST) anomalies in key regions of the Pacific Ocean over winter and spring and provides objective outlooks for summer rainfall on this basis. For the current summer (November to March 2016/17), the Science Division of DSITI considered that, for most of Queensland, the probability of exceeding median rainfall was higher than normal. Read more (PDF, 203K, last updated 02:28PM, 15 February 2017)*
The SST regions that DSITI monitors are linked to the El Niño-Southern Oscillation (ENSO) phenomenon and also reflect a more slowly changing, extra-tropical SST signal. Leading into summer, SSTs in the Niño 3.4 region of the central equatorial Pacific were cooler than normal and bordering on La Niña thresholds. In contrast, SSTs in the south-western Pacific were warmer than normal, reinforcing the emerging La Niña SST pattern. The Southern Oscillation Index (SOI) was also tracking close to La Niña thresholds.
Although weak La Niña conditions were observed in spring and early summer, the Bureau of Meteorology and international climate agencies now classify current conditions as ‘ENSO-neutral’. In January the Niño 3.4 SST anomaly was -0.3oC and the SOI +0.5. Over the last three-month (November to January) period, the average Niño 3.4 SST anomaly was -0.4oC and the average value of the SOI was +0.5. Rainfall recorded in Queensland over the November to January period ranged from extremely-high in some northern and western areas of the state to extremely-low in parts of central and south-eastern Queensland.
Prior to summer, the Bureau of Meteorology advised that Queensland will most likely experience a near-average tropical cyclone season (November to April). A near-average tropical cyclone season would be defined as a season where one or two tropical cyclones cross the Queensland coast. While no tropical cyclones have occurred in the Queensland region so far this cyclone season, the occurrence of one or more tropical cyclones remains possible through to the end of April.
It should be noted that seasonal outlooks are probabilistic, rather than deterministic, in nature. Although outcomes with a high probability may be more likely, this does not mean that less probable events will not occur in any given year. In issuing the outlook for the current summer, DSITI advised that an increased probability of above-median rainfall for Queensland will not necessarily result in above-median rainfall throughout all of the state. Given that some parts of the state have had extremely-low rainfall so far this summer, it is now unlikely that rainfall in those areas will be above-median for the November to March period.
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