Subseasonal to Seasonal Climate Forecasts Provide the Backbone of a Near-Real-Time Event Explainer Service

The Australian Bureau of Meteorology (BoM) provides forecasts at daily, multiweek, and seasonal time scales along with a range of other services. Customers are keen to be informed about the causes of extreme weather and climate events to help them in their planning and decision making. While attribution is often framed in terms of understanding the role of climate change, it is also useful to understand the role of climate variability and circulation changes in causing extreme events (e.g., Mindlin et al. 2020).The focus of the Event Explainer is to reduce climate risk by informing decision makers about the causes of extreme events and, if there are persistent underlying drivers, the event’s likelihood of recurrence over the coming season or decade. This article describes the tools that are being developed at the BoM to explain the causes of extreme weather and climate events, and how those tools would add value to existing services. The novel aspect of the tools is that they will link with the dynamical subseasonal to seasonal (S2S) forecasts currently in operation. Thus, operational staff are alerted to the upcoming extreme event, and have time to diagnose and quantify the causes, thereby facilitating earlier and more effective communication with the public and stakeholders and potentially tailoring the service to users’ needs. Hence there is strong appeal in using an operational forecast system as the backbone of a real-time attribution system.