The Alps are situated between a depression over the British Isles and a high over southeastern Europe, and the large pressure gradient across the Alps forms a typical foehn nose. A secondary area of low pressure is located over the western Mediterranean Sea.
It is evident that the 20CR can resolve the large-scale flow, but the foehn nose and the potential area of low pressure over the Mediterranean in Fig.
2d, MSLP contours delineate the foehn nose, and minimum MSLP values near 990 hPa are found in the foehn regions, which results in a pressure difference of approximately 16 hPa in the DEM (14 hPa in #27,6 hPa in #51) across the Alps.