Figure 1

2018 July (a) 2-m temperature anomalies (shading, °C) and (b) 500-hPa geopotential height anomalies (shading, m) and absolute 500-hPa geopotential height (contour, m). The solid contours are 5600, 5700, and 5800 m, and dashed contour is 5750 m. Anomalies are relative to the period of 1999–2010. Boxes show the area used to define Scandinavia (SC) and Western Europe (WE). Regression of 2-m temperature anomalies (shading, °C) and 500 hPa geopotential height anomalies (shading, m) onto the monthly circulation indices (c) NAO and (d) SCA. Contour interval is 2; solid and dashed contours for positive and negative correlation coefficients, respectively, and gray color for zero contours. NAO North Atlantic Oscillation, SCA Scandinavia Pattern. See text for details of the data sources. The linear regression analyses were conducted over the period of July 1999–2018. The maps were generated using software NCAR Command Language (https://www.ncl.ucar.edu/)³² with the built-in Ncarg4_0 database.