Drift of the Gulf Stream towards its northern limit over the last half-century

Abstract The latitude of the north wall of the Gulf Stream along the US seaboard has been recorded in the Gulf Stream North Wall (GSNW) Index for over half a century from 1966 to 2023. The first half of this series shows the position fluctuating about a steady northward drift but this drift ceased in the second half. The same abrupt change is seen in the data of Joyce et al. from 200m depth which begin back to 1954 and extend further east. Monthly values of the GSNW index have been used to estimate how the occurrence of extreme meanders has changed over the 58-year period. Southern extremes follow the same pattern of change as the annual average positions but northern extremes show no northward drift. It may be the Gulf Stream has approached its northern limit. The transition has accompanied the rise in the number of warm-core rings observed by Gangopadhyay and colleagues and this may have been part of the process preventing further northward drift.