This article isn't citing any sources, but here is a relevant article from the NOAA: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/en

This article isn't citing any sources, but here is a relevant article from the NOAA: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/e...