The Department of Science, Information Technology and Innovation’s (DSITI’s) seasonal outlooks for the Queensland summer are based on the state of the El Niño–Southern Oscillation (ENSO) phenomenon prior to summer, and on factors which alter the impact of ENSO on Queensland rainfall (i.e. the more slowly changing extra-tropical sea surface temperature (SST) pattern in the Pacific Ocean). The Science Division of DSITI considers that, for most of Queensland, the probability of exceeding median rainfall for summer (November to March 2016/17) is currently slightly higher than normal. This view is based on an analysis of the March extra-tropical Pacific Ocean sea surface temperature (SST) pattern. Read More (PDF, 367K, last updated 12:03PM, 18 April 2016)*
At this time of year (known as the ‘autumn predictability gap’), the ENSO pattern tends to change very rapidly. Although the change in the ENSO pattern over autumn may provide a guide as to the likely development of El Niño or La Niña events, it is not until late autumn (May) that the prevailing ENSO pattern (as measured by indices such as the SOI or central equatorial Pacific Ocean SST anomalies) begins to provide a useful basis for seasonal forecasting (i.e. for providing rainfall outlooks for winter, spring or summer). However, it is useful to monitor the change in ENSO indices over this time of year as a guide as to whether an El Niño or La Niña pattern may develop. Global climate models also provide a more formal means of assessing this likelihood.
DSITI scientists have shown that extra-tropical SST anomalies, when measured in specific regions of the Pacific Ocean in March each year, provide a useful basis for long-lead forecasting of summer (November to March) rainfall in Queensland. The accuracy of this outlook increases as the evolving ENSO-related SST pattern is also taken into account from May through to October. This understanding has been incorporated in an experimental system known as SPOTA-1 (Seasonal Pacific Ocean Temperature Analysis version 1), which has been operationally evaluated by DSITI scientists for over a decade.
As at 1 April 2016, DSITI’s initial long-lead outlook for summer (November to March 2016/17) indicates a slightly higher than normal probability of exceeding median rainfall for most of Queensland. This outlook indicates that warmer than normal extra-tropical SSTs currently east of Australia may have a favourable influence on Queensland summer rainfall.
In summary, it should be noted that:
Updates to the summer rainfall outlook will be reported in future Monthly Climate Statements.
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