During September, the ENSO Region 1+2 anomaly fell below -1.00°C for multiple weeks. Since 1950, only a single El Niño winter (2002-03) followed a September with one such week. Therefore, based on a combination of the current guidance and historical ENSO data, the underlying ENSO assumption for winter 2019-2020 is a neutral (warm) ENSO state. There could be periods where the ENSO Region 3.4 anomaly is somewhat above +0.5°C, but the winter average should be neutral. For much of the winter the Reg