Convection-Allowing Applications of FV3 at EMC

In August 2016, the Finite-Volume Cubed-Sphere (FV3) dynamical core was chosen by NOAA as the next generation global prediction system (NGGPS). The FV3 will be implemented at NCEP’s Environmental Modeling Center (EMC) as part of the operational GFS upgrade in early 2019, labeled as FV3GFS. For the most part, FV3GFS uses operational GFS physics with slight modifications, except it uses the GFDL microphysics scheme instead of Zhao-Carr. At the convection-allowing scale, EMC currently maintains several different NWP modeling systems, including the North American Mesoscale (NAM), the High Resolution Rapid Refresh (HRRR), and three different High Resolution Window (HIRESW) models. EMC plans to consolidate its mesoscale modeling suite by unifying around the FV3 dynamical core, pending a favorable scientific evaluation.

Two separate but related efforts are currently underway at EMC with regards to the development of a convection-allowing FV3 model. An experimental 3-km FV3 nest within the global FV3 domain has been run once a day since April 2018. Furthermore, a stand-alone regional version of the FV3 model is under development, also featuring daily real-time runs. Both configurations are initialized off of EMC’s daily FV3GFS forecasts, currently running four times a day in parallel to the operational GFS. Several noteworthy severe storm cases as well as preliminary verification statistics will be used to examine the regional nest and stand-alone configurations of FV3.