Seasonal predictions in the Mediterranean region have relevant socio-economic implications, especially in the context of a changing climate. To date, sources of predictability have not been sufficiently investigated at the seasonal scale in this region. To fill this gap, we explore sources of predictability using a weather regimes (WRs) framework. The role of WRs in influencing regional weather patterns in the climate state has generated interest in assessing the ability of climate models to reproduce them. We identify four Mediterranean WRs for the winter (DJF) season and explore their sources of predictability looking at teleconnections with sea surface temperature (SST). In particular, we assess how SST anomalies affect the WRs frequencies during winter focussing on the two WRs that are associated with the teleconnections in which the signal is more intense: the Meridional and the Anticyclonic regimes. These sources of predictability are sought in five state-of-the-art seasonal forecasting systems included in the Copernicus Climate Change Services (C3S) suite finding a weaker signal but an overall good agreement with reanalysis data. Finally, we assess the ability of the C3S models in reproducing the reanalysis data WRs frequencies finding that their moderate skill increases during ENSO intense years, indicating that this teleconnection is well reproduced by the models and yields improved predictability in the Mediterranean region.

地中海地区的季节性预测具有相关的社会经济影响，尤其是在气候变化的背景下。迄今为止，尚未对该地区的季节性尺度的可预测性来源进行充分的调查。为了填补这一空白，我们使用天气方案（WRs）框架探索可预测性的来源。WR在影响气候状态下区域天气模式中的作用引起了人们对评估气候模型重现它们的能力的兴趣。我们确定了四个冬季（DJF）的地中海WR，并通过与海表温度（SST）的遥相关来探索它们的可预测性来源。尤其是，子午线和反气旋政权。这些可预测性来源在哥白尼气候变化服务（C3S）套件中包括的五个最新的季节性预测系统中寻求，它们发现信号较弱，但与再分析数据总体上吻合良好。最后，我们评估了C3S模型在再现重新分析数据WR频率时的能力，发现它们的适度技能在ENSO紧张的岁月中有所增加，这表明该遥距连接已被模型很好地再现，并提高了地中海地区的可预测性。