The HARMONIE–AROME Model Configuration in the ALADIN–HIRLAM NWP System

The aim of this article is to describe the reference configuration of the convection-permitting numerical
weather prediction (NWP) model HARMONIE-AROME, which is used for operational short-range
weather forecasts in Denmark, Estonia, Finland, Iceland, Ireland, Lithuania, the Netherlands, Norway,
Spain, and Sweden. It is developed, maintained, and validated as part of the shared ALADIN–HIRLAM
system by a collaboration of 26 countries in Europe and northern Africa on short-range mesoscale NWP.
HARMONIE–AROME is based on the model AROME developed within the ALADIN consortium.
Along with the joint modeling framework, AROME was implemented and utilized in both northern and
southern European conditions by the above listed countries, and this activity has led to extensive updates to
the model’s physical parameterizations. In this paper the authors present the differences in model dynamics
and physical parameterizations compared with AROME, as well as important configuration choices of the
reference, such as lateral boundary conditions, model levels, horizontal resolution, model time step, as well
as topography, physiography, and aerosol databases used. Separate documentation will be provided for
the atmospheric and surface data-assimilation algorithms and observation types used, as well as a sepa-
rate description of the ensemble prediction system based on HARMONIE–AROME, which is called HarmonEPS.