Decadal predictability of late winter precipitation in western Europe through an ocean–jet stream connection

Abstract

The characteristics of the North Atlantic jet stream play a key role in the weather and climate of western Europe. Although much of the year-to-year variability in the jet stream arises from internal atmospheric processes that are inherently unpredictable on timescales beyond a few days to weeks, any low-frequency variability or long-term trends that can be considered forced by slowly varying boundary conditions offer the potential for extended range predictability of climatological conditions in western Europe. Here we demonstrate that station-based precipitation observations have displayed pronounced multidecadal variability over the past century in western Europe during the late winter. We then use these precipitation observations as an independent verification of the multidecadal Atlantic jet stream variability found in reanalysis products. Both signals are highly correlated with sea surface temperature variability in the North Atlantic that is well predicted in initialized decadal prediction experiments with a coupled general circulation model. Combining the model-based predictions of the sea surface temperature with the observed relationship between precipitation and sea surface temperature, we show that there is great potential for skilful predictions of the forthcoming decadal average of March precipitation in western Europe, with hindcasts for the UK and Portugal yielding anomaly correlation coefficients of 0.82 and 0.69, respectively. Decadal averages of March precipitation in western Europe can be predicted by exploiting links with the jet stream and ocean along with skilful predictions of sea surface temperatures, according to an analysis of observations and reanalysis products.