Variable-Resolution Tropical Cyclone Prediction Using the Model for Prediction Across Scales (MPAS)

Abstract:

The Model for Prediction Across Scales (MPAS) was used to produce three months of global forecasts of tropical cyclones (TCs) across the Northern Hemisphere in 2014 and 2015. The results from fixed-resolution (15 km) and variable-resolution (ranging from 60 km to 15 km) 10-day forecasts will be compared, with a focus on the East Pacific in 2014 domain because of its high-level of TC activity. In the variable-resolution MPAS, the 15-km mesh covers the region from the Central Pacific to Central America. It will be shown that the variable-resolution MPAS performed nearly as well as the uniform resolution over the Eastern Pacific basin. Both produced track forecasts of comparable quality to the NCEP Global Forecast System (GFS). Forecasts over the tropical East Pacific revealed only slowly growing differences between uniform and variable resolution through day 7. The results collectively indicate that variable resolution global simulations represent an efficient way to produce basin-scale TC forecasts while still including upscale TC influences on the global circulation. In addition, we will show improvements in TC genesis and intensity statistics introduced by changes to physical parameterizations for forecasts performed during the 2015 Northern Hemisphere TC season (August-October).