Can S2S Predictions Improve Disaster Risk Preparedness for the Southeast Asia Region? A Review of June 2020

Southeast Asia is in a prime position to benefit from S2S products. The region is one with the highest skill at the S2S timescale, and being exposed to several hydrometeorological hazards, makes an ideal candidate for exploring benefits from S2S climate services. For example, between the 15^th and 28^th June 2020, more than 20,000 people were affected by floods in Indonesia, Thailand and Malaysia, with damages reported to more than 2000 houses, agricultural land and infrastructure (AHA Centre's Weekly Disaster Updates). However, moving from research into practical applications faces several challenges. The ASEAN Specialised Meteorological Centre (ASMC) and partners (Economic and Social Commission for Asia and the Pacific, UN ESCAP, Regional Integrated Multi-Hazard Early Warning System for Africa and Asia, RIMES, and AHA Centre) are working to develop S2S products in Southeast Asia. Projects include an S2S workshop series, from which UN ESCAP lead the development of an S2S primer for disaster risk reduction (DRR) in Southeast Asia. ASMC and partners have also started a real-time pilot project for DRR. These projects aim to develop a regional set of S2S products for use in conjunction with national-level products.

Through the lens of the June 2020 case study, we review the progress so far in developing regional S2S products for DRR in Southeast Asia. Based on the standard weekly anomaly precipitation and 90^th percentile plots, wetter conditions were forecasted for the equatorial region (where there is good hindcast skill) four weeks beforehand, increasing in severity and likelihood as the event approached. This case study presents AHA Centre's experience in using these forecasts to focus their monitoring efforts, in conjunction with NMHSs weather forecasts. However, while the AHA Centre is an experienced meteorological data user, communicating S2S information to users less familiar with climate science has proved tricky. Furthermore, progress in developing tailored products has been slow due to communication gaps between the forecast producers and users and capacity in the region. Beyond a summary of lessons learnt, we also discuss whether the standard regional S2S products can be used for S2S climate services, or whether only tailored sub-region products are truly useful.