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Strength in partnership

Tropical cyclones are notoriously difficult to predict. But recent improvements to the Met Office forecasting model and an exciting partnership with the Philippines are helping improve forecast accuracy and mitigate what can be devastating impacts.

In 2013, Typhoon Haiyan wreaked havoc across the Philippines, leaving over 6,000 people dead and millions displaced. It was one of the most powerful tropical cyclones ever recorded - and the Met Office saw it coming. However, while the global model may have predicted the storm's track accurately, it underestimated its intensity.

This is an issue for any global model; while their resolution is improving as increased computer power becomes available, it's still not enough to replicate the conditions at a tropical cyclone's typically compact centre, where winds can reach 190 mph and pressure as low as 900 millibars. But this is changing.

Better model, better predictions

Last July, we implemented major improvements to our global model. While these weren't specifically aimed at improving tropical cyclone prediction, this was the area in which they had the biggest impact. Besides improving intensity predictions, tracking predictions improved by almost nine percent.

An even more recent change has taken advantage of the observational estimates made by tropical cyclone warning centres around the world. Assimilating these data into the global model has improved tracking predictions by another six percent. We are also testing a high-resolution regional model using a fixed domain over the Philippines. Once our supercomputer is online, this regional model will be implemented in realtime over every tropical cyclone that's occurring at any one time.

This is just one of the projects we are running in partnership with the Philippines' weather service, the Philippine Atmospheric, Geophysical and Astronomical Service Administration (PAGASA). Besides supplying data feeds from the Met Office Unified Model (UM) - the Met Office is also helping PAGASA raise its in-country capability by offering training and developing impact forecasts to support the responder community. This year, with the Met Office's assistance, PAGASA plans to acquire a supercomputer so that it can become a UM partner and run regional models itself.

Forecasting Typhoon Hagupit

The strength of this partnership was demonstrated when Typhoon Hagupit hit in December 2014. Unlike Typhoon Haiyan, this was very hard to predict, with global models from different meteorological services around the world giving different forecasts of the typhoon's track. This made it difficult for PAGASA to assess and supply accurate information to government and the public.

The Met Office Global Guidance Unit (GGU) stayed in touch with PAGASA, running additional models and connecting regularly on Skype. "Because we had a closer partnership with them, we had better lines of communication and it was much more two-way," explains Julian Menadue, Senior International Development Manager.

As Dr Vicente B. Malano, Acting Administrator of PAGASA, said, "The guidance documents and invaluable insights provided were really very helpful and guided us to better understand Typhoon Hagupit's behaviour and validate our forecast. This heightened our capacity to assess the different models and provided the opportunity to enhance our capability in weather forecasting."

This partnership is set to continue. This year, the Met Office is working with both PAGASA and the Department for International Development (DFID) to provide technical assistance - including the latest climate modelling - and inform how Philippine infrastructure, including roads, can be rebuilt to be more resilient and less vulnerable to tropical cyclones.