Arcus cloud Arcus cloud An arcus cloud is a low, horizontal cloud formation, usually appearing as an accessory cloud to a cumulonimbus. Roll clouds and shelf clouds are the two main types of arcus. Arcus clouds most frequently form along the leading edge or "gust fronts" of thunderstorm outflow; some of the most dramatic arcus formations mark the gust fronts of derecho-producing convective systems. Roll clouds also may arise in the absence of thunderstorms, forming along the shallow cold air currents of some sea breeze boundaries and cold fronts. A shelf cloud is a low, horizontal, wedge-shaped arcus cloud. A shelf cloud
UK Government G-Cloud COO of GDS, took over as director of G-Cloud. A new version of the G-Cloud framework is normally released about every 6 to 9 months. G-Cloud version 9 went live in May 2017; as of November 2017, the release date for version 10 had not been finalised. G-Cloud had several calls for contract to establish framework agreements. Major US vendors Amazon Web Services (AWS) and Google were initially excluded by the UK government in 2012 (G-Cloud 3) but AWS has since been added in 2013 (G-Cloud 4). Following hints by the head of the programme, GDS chief operating officer Tony