Abstract
Data assimilation (DA) methods combine a prior forecast (background state) with the latest observations of the atmosphere, to estimate the initial conditions for a weather forecast. Accurate and early forecasts of extreme weather events allow time for actions to be taken to protect populations from injury and death, and for the preservation of infrastructure as far as possible. Climate change is expected to increase the severity frequency of some extreme weather events over the coming Century. Advances in DA should improve the forecasts of these events.