Prediction and Dynamics of Super Typhoon MEGI (2010)

Super Typhoon MEGI, forming over the Northwestern Pacific in October 2010, was the strongest tropical cyclone over the whole globe last year, with the top intensity of maximum winds up to 72 m/s and minimum sea level pressure of 895hPa. After striking northern Philippines and entering eastern South China Sea, the westward moving MEGI turned sharply northwards, with almost 90 degrees to the right. MEGI's sharp northward-turning in track posed big challenges to operational numerical weather prediction models and forecasters. China Meteorological Administration (CMA)'s official forecast errors for MEGI's track were much bigger than the 2010 average. The forecast error was particularly big for MEGI's landfalling location while issuing typhoon warnings to the coastal areas in South China. Using observational data, reanalysis and TIGGE forecast data as well as cloud-resolving ensemble simulations with the Weather Research and Forecast (WRF) model, this study examines the forecast uncertainties in different operational NWP centers and the predictability and dynamics of this supertyphoon. We are particularly interested in the cuases that are responsible for the storm's sudden track changes in nature, the forecaster's judgment under inherent uncertainties of the numerical guidance, and the lessons we learn from this unusual case for predicting future extreme events at the operational forecast centers.