THORPEX: a Global Atmospheric Research Programme is an international research programme to accelerate improvements in the accuracy of 1 to 14-day weather forecasts for the benefit of society and the economy. Due to the high-impact weather and significant errors in numerical weather prediction associated with extratropical transition it is one of the specific weather systems that will be investigated as part of THORPEX. This paper will give a brief overview of THORPEX and discuss the role of ET in this research programme.