The PALM model system. PALM is an advanced and modern meteorological model system for atmospheric and oceanic boundary-layer flows. It has been developed as a turbulence-resolving large-eddy simulation (LES) model that is especially designed for performing on massively parallel computer architectures. Since PALM 5.0, the model is shipped along with several PALM-4U (PALM for urban applications, read: PALM for you) components that allow to employ the model for various urban applications ranging from the meso- to the microscale. The PALM model system is free software. It can be redistributed and/or modified under the terms of the GNU General Public License (v3). We kindly request that you cite PALM in all your publications. For details, see citing PALM.