Arcus cloud is attached to the base of the parent cloud, which is usually a thunderstorm cumulonimbus, but could form on any type of convective clouds. Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent and wind-torn. Cool, sinking air from a storm cloud's downdraft spreads out across the land surface, with the leading edge called a gust front. This outflow cuts under warm air being drawn into the storm's updraft. As the lower cooler air lifts the warm moist air, its water condenses, creating a cloud which often
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