Rainfall Forecasts for Tropical Cyclones Worldwide

Severe rainfall from tropical cyclones can cause loss of life and destruction comparable or greater than that from the storms high winds. For example, severe rainfall from tropical cyclones striking Asia causes hundreds of deaths annually, whilst in the U.S. 59% of all tropical cyclone deaths between 1970 and 1999 were due to inland flooding. Currently there are few tools which provide warnings of the risk of heavy rainfall from active tropical storms worldwide. In February 2007 the Tropical Storm Risk (TSR) venture, based at University College London, launched a graphical quantitative and probabilistic rainfall forecasting application as part of its award-winning Tropical Storm Tracker. This product is accessible through the website http://www.tropicalstormrisk.com. It is underpinned by rainfall forecasts from the UK Met Office's Global numerical weather prediction model combined with considerable in-house research and modelling. The product's features include a) Quantitative rainfall forecasts giving the total rainfall at a given point over leads of 1,2,3,4 and 5 days; b) Probabilistic rainfall forecasts giving the likelihood of 5 cm, 12.5 cm and 15 cm of rainfall at a given location; c) Updated forecasts every 12 hours; d) Observed rainfall rates and totals for the last 3 hours and last 7 days. The new application will help insurers, re-insurers and risk managers to assess better the risk of intense rainfall and inland flooding, and will benefit humanitarian relief agencies by helping them to more effectively plan their emergency response when storms target populated areas.