New methods for temperature downscaling in complex terrain

The current horizontal resolution of operational numerical weather prediction models implies that the variability of air temperatures in hilly areas is usually under-represented. To improve the quality of the forecast, it is therefore necessary to develop downscaling techniques, which present a number of challenges. For instance, the height difference between the model and downscaled terrain must be accounted for, requiring an estimate of the height variation of temperature. Further, the local terrain morphology influences sheltering and cold air drainage. We summarise some developments and ongoing work related to downscaling Met Office temperature forecasts in hilly terrain, some of which have been applied to site-specific and route-based temperature forecasting.