Fig. 1: NAO index patterns and precipitation anomalies in December 2023.
From: Increased persistence of warm and wet winter weather in recent decades in north-western Europe
a Kernel density estimates of the NAO index in winter for 1950–1980 in orange and 1990–2020 in red. The vertical dashed line represents the mean of the NAO index in December 2023. b NAO index in December 2023. The vertical dashed line depicts the arrival of Storm Henk. c Absolute difference in percentage of days with precipitation (0.5mm/day or more precipitation) for weather stations across Europe between December 2023 and the December months of 1950–2020. d Absolute difference in accumulated precipitation between December 2023 and the December months of 1950–2020 for weather stations across Europe. (1)–(5) denote recorded floods in the UK (1), northern France (2), eastern Germany (4) and southern Denmark (5)9,10. Record-high water levels were recorded in the Netherlands (3)11.
