  Projected changes in summer precipitation deficits partly depend on
alterations in synoptic circulations. Here, the automated Jenkinson-Collison
(JC) classification is used to assess the ability of twenty-one Global Climate
Models (GCMs) to capture the frequency of recurring circulation types (CTs) and
their implications for European daily precipitation intensities in summer
(JJA). The ability of the GCMs to reproduce the observed present-day climate
features is first evaluated. Most GCMs capture the observed links between mean
directional flow characteristics of the CTs, and the occurrence of dry days and
related dry months. The most robust relationships are found for anticyclonic
and easterly CTs which are generally associated with higher than average
occurrences of dry conditions. Future changes in summer frequencies of the CTs
are estimated in the high-emissions SSP5-8.5 scenario for the sake of a high
signal-to-noise ratio. Our results reveal consistent changes, mainly in the
zonal CTs. A robust decrease in frequency of the westerlies and increase in the
frequency of easterly CTs favour more continental, dry and warm air masses over
Central Europe. These dynamical changes are shown to enhance the projected
summer drying over central and southern Europe.
