The Department of Science, Information Technology and Innovation (DSITI) 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. The Science Division of DSITI considers that, for next summer (November to March), rainfall probabilities are currently near-normal for much of Queensland. Read more (PDF, 169K, last updated 09:20AM, 14 June 2017)*
DSITI provides seasonal outlooks for summer rainfall in Queensland, based on SST anomalies in key regions of the Pacific Ocean which have the most relevance for summer rainfall in Queensland. The current outlook is based on SST anomalies in the extra-tropical Pacific Ocean in March and SST anomalies in key regions of the Southwest Pacific Ocean in May. SST anomalies in the Southwest Pacific are strongly related to the El Niño-Southern Oscillation (ENSO)phenomenon.
Values of key ENSO indices have been within ENSO-Neutral thresholds over the last three-month period (March to May). In particular, the average three-month Niño 3.4 SST anomaly was +0.3°C and the three-month average value of the Southern Oscillation Index (SOI) was -0.6. At this time of the year, the relationship between ENSO indices and rainfall for the season ahead is very weak. However, by mid-winter this relationship begins to strengthen and ENSO-related indices such as the SOI and Pacific Ocean SST anomalies become more reliable for seasonal forecasting. Therefore, DSITI will closely monitor ENSO-related indices over the coming months.
DSITI will provide updated outlooks for summer rainfall, each month from July to November, to take into account developments in the ENSO-related SST pattern during that period. The outlooks are produced by DSITI’s Seasonal Pacific Ocean Temperature Analysis version 1 (SPOTA-1) system.
It should be noted that seasonal outlooks are probabilistic, rather than deterministic, in nature. For example, if an outlook is described as having a 60 per cent probability of exceeding-median rainfall, there is also a 40 per cent probability of below-median rainfall. In cases where outcomes with a high probability may be more likely, this does not mean that less probable events will not occur in any given year.
As noted, DSITI will provide updates outlooks for summer rainfall each month from July to November. The next outlook for summer will factor in the ENSO-related SST pattern in June.
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