A synoptic overview of the EUREC⁴A field campaign

We present an overview of the important synoptic features that occurred during the EUREC⁴A field campaign. These results are based on workshops bringing together forecasters and researchers to look in detail at cloud patterns in the region of interest (Barbados and the upstream trade winds) and how they were influenced by synoptic features. Consistent with previous studies, we found that the influence of, or lack of, midlatitude and subtropical features was important for cloud patterns. The strength and position of subtropical high pressure systems strongly varied through the field campaign and could be linked to differences in cloud patterns as well as the transport of dry and dusty air from West Africa. Development of deeper clouds and more organised patterns typically coincided with an upper level potential vorticity streamer associated with anticyclonic Rossby-wave breaking. The local Hadley circulation shows a strong climatological subsidence in the region of interest, but had a positive anomaly for ascent during the field campaign, indicating favourable conditions for cloud development, albeit with substantial day-to-day variability. There was often much more detail in cloud patterns in any given satellite image than can be conveyed in a summary. Two features of note were flowers cloud pattern along the boundary of dry and dusty air without dominating the region, and fish cloud patterns could be embedded within other types of cloud pattern with no associated front or shear line.