Comparison of ocean temperature patterns, wind shear, and hurricane activity during the positive phase of the Atlantic Meridional Mode (left) and the negative phase (right). The positive phase brings warmer than average surface temperatures in the tropical Atlantic (orange and red) and lower than average wind shear (dashed contour lines), favoring more named storms (start locations marked with plus signs) and major hurricanes (circled plus signs). The negative phase favors the opposite: cooler-than-average surface temperatures, higher than average wind shear (solid contour lines), and fewer storms. Figure adapted from Kossin and Vimont, 2007.