In this study, we analyse the influence of North Atlantic midwinter storm track suppressions on European synoptic temperature and precipitation anomalies to determine the large-scale conditions relevant for the so-called Christmas thaw. We diagnose this relation in daily ERA5 reanalysis data in the spatial resolution of 0.25^∘ between 1979 and 2018. To access synoptic time scales, a 3–10-day band-pass filter is applied. An index for the suppression is defined by the upper tropospheric Eddy Kinetic Energy (EKE) anomalies in the North Atlantic. We define the strong jet stream years as the year exceeding the 75% of the winter seasonal values at 250 hPa. In winters with strong jet activity, the storm track suppression is found, in agreement with the barotropic governor mechanism. Composites of European surface temperature and precipitation for low index values reveal weakly warmer conditions during winter (DJF) in Central Europe and the British Isles and a distinct cooling in Northern Europe. In the 1-month interval during December 15 to January 15, the warming is more pronounced. The clearest signal is the precipitation increase with a magnitude of 1 mm/day in the Mediterranean region.

在这项研究中，我们分析了北大西洋冬季风暴路径抑制对欧洲天气温度和降水异常的影响，以确定与所谓的圣诞节解冻有关的大规模条件。我们在0.25的空间分辨率诊断日常ERA5再分析资料这个关系^∘在1979年至2018年之间。为访问天气尺度，应用了3-10天的带通滤波器。抑制的指标由北大西洋对流层上的涡动能（EKE）异常确定。我们将强喷射流年定义为超过250 hPa的冬季季节性值的75％的年份。在具有强烈射流活动的冬季，与正压调速器机制相一致，发现了风暴轨迹的抑制。低表面指数值的欧洲地表温度和降水的复合物显示，中欧和不列颠群岛的冬季（DJF）的天气较弱，北欧则明显冷却。在12月15日至1月15日的1个月间隔中，变暖更为明显。