Dynamical precursors to summer temperature extremes on the Antarctic Peninsula

Abstract. Extreme warm summer near-surface temperatures over the Antarctic Peninsula (AP) can lead to surface melting and the disintegration of ice shelves. While individual case studies have linked such events to anomalous large-scale circulation, a systematic assessment of the dynamical pathways leading to AP-wide extreme austral summer warm events remains limited. This study uses ERA5 reanalysis data to investigate the large-scale dynamical precursors associated with extreme warm days over the Antarctic Peninsula. We apply k-means clustering to mean sea level pressure anomalies during high temperature extremes and identify five distinct circulation patterns with different dominant zonal wavenumbers. We investigate the spatio-temporal evolution and persistence of near-surface wind, temperature and pressure for each cluster. Four clusters are associated with rapidly amplifying planetary-scale wave patterns, while a fifth resembles a negative Southern Annular Mode–like state with enhanced persistence prior to event onset. Despite these differing pathways, all regimes promote anomalous northerly flow toward the AP, driving strong meridional temperature advection and regional warming. We demonstrate that extreme Antarctic Peninsula warm events arise from distinct circulation pathways, reflecting diverse dynamical states likely influenced by hemispheric-scale teleconnections and planetary wave interactions.