This document reports the results of an e-infrastructure evaluation performed by the Improved Observation Usage in NWP (iOBS) project. The goal was to evaluate how future e-infrastructure for numerical weather prediction (NWP) could make use of cloud and high-performance computing (HPC) resources. New kinds of computing infrastructure is needed to tackle challenges coming from both data ingestion of crowdsourced data and integration of machine learning components to standard IT systems. As HPC has always been central to NWP this work focused primarily on the possibilities of cloud technologies.