August was another above-average month for tropical activity in the basin. Pressures across most of the western Pacific were lower than average, particularly around Okinawa where tropical cyclone activity was high during the month. Between August 10–19, a progression of cyclones in the upper troposphere triggered wind perturbations closer to the ocean surface, leading to the genesis of Tropical Storm June, Typhoon Kathy, Tropical Storm Lorna, and Tropical Storm Nancy. Typhoons Kathy and Marie were involved in a Fujiwhara interaction that led both storms to rotate counterclockwise around each other, ending with Marie's absorption into Kathy's circulation. A paper published in the "Quarterly Journal of the Royal Meteorological Society" described the resulting paths of the two storms as an "archetypal example" of the Fujiwhara interaction. In September, tropical cyclone activity was high across the Northern Hemisphere in both the Atlantic and Pacific. Subtropical ridging in the Pacific was extended zonally throughout the month, resulting in strong easterly winds in the subtropical latitudes and providing conducive conditions for storm development. The extensive ridging also prevented most of September's storms from taking curved paths into the westerlies; while approximately half of September typhoons curve into the westerlies on average, only one typhoon, Wilda, took such a trajectory in 1964. The strong substropical ridging continued into October, leading to similar storm paths.