Was the extremely wet winter of 2018/2019 in the lower reach of the Yangtze River driven by El Niño–Southern Oscillation?

In the winter of 2018/2019, the lower reach of the Yangtze River (LRYR) of China experienced an excessive amount of precipitation with a long duration. Such an extreme event occurred in the mature phase of an El Niño under the background of global warming, and thus, attracted great attention in the society and climate community. Presumably, this extreme event was driven by the El Niño. In this work, based on observational diagnoses and real‐time model forecasts, we investigate the contributions of oceanic forcing and the predictability of this event. It is argued that tropical Atlantic warming, interdecadal variation, and central tropical Pacific warming (associated with Central Pacific [CP] instead of Eastern Pacific El Niño) are three major factors leading to the extreme event. In addition to the recognized impact from sea surface temperature anomalies (SSTAs) associated with CP El Niño, tropical Atlantic warming makes an important contribution to the Atlantic‐Eurasian circulation change through a global zonal wave pattern extending from the tropical Atlantic to East Asia. Moreover, a climate model successfully predicted the wet pattern in LRYR in short (1–5 month) lead real‐time predictions, and captured the observed statistical relationship between the winter precipitation in LRYR and the SSTA in the central tropical Pacific and equatorial Atlantic Oceans. These results indicate that such an event is predictable to some extent. Tropical Atlantic warming, interdecadal variation, and central tropical Pacific warming (associated with Central Pacific instead of Eastern Pacific El Niño) are three major factors leading to the extremely wet winter of 2018/2019 in the lower reach of the Yangtze River (LRYR). The real‐time prediction results of successfully captured the observed statistical relationship between the winter precipitation in LRYR and the sea surface temperature anomaly (SSTA) in the central tropical Pacific and equatorial Atlantic Oceans indicates that such an event is predictable to some extent. The figure shows the reconstructions of December–January–February (DJF) 2018/2019 precipitation anomaly based on the linear regression with the detrended (a) central Pacific El Niñoand (b) Atlantic Niño SST indices; (c) the interdecadal change of the DJF precipitation in 1989/1990–2018/2019 and 1951/1952–1988/1989; (d) the sum of (a), (b) and (c)