The Impact on Tropical Cyclone Predictions of a Major Upgrade to the Met Office Global Model

A major upgrade to the Met Office Global Model is planned for implementation before the middle of 2014. This includes a major revision to the model's dynamical core, improved physics and increased horizontal resolution to about 17 km at mid-latitudes.

The impact of these changes on tropical cyclone predictions has been assessed during trials covering the periods June-September 2012 and November-December 2012. Track forecast errors were considerably reduced in these trials, with most of the impact arising as a result of the model dynamics and physics changes. The changes have also had a significant positive impact on tropical cyclone intensity, resulting in stronger storms and reductions in mean absolute errors of both mean sea-level pressure and near surface winds. Both the change in resolution and the change to model dynamics and physics contributed to the improvement in intensity predictions.

This paper will present the results of trials on tropical cyclone track and intensity predictions and cite specific examples of where the model performance was greatly improved by the package of changes.