El Nino and shipping: ENSO as an operational variable

The El Nino Southern Oscillation is the dominant mode of interannual climate variability in the tropical Pacific, and it reaches shipping mainly through rainfall. An El Nino phase suppresses precipitation over the Panama Canal watershed, which lowers Gatun Lake and forces the Panama Canal Authority to reduce authorized drafts and ration transit slots.

The full article will cover the mechanism, the forecasting horizon a charterer can actually act on, and the named consequences: canal draft restrictions, low water on the Rhine and the Mississippi, altered monsoon timing on Indian Ocean routes, and shifts in tropical cyclone distribution. It will also treat how forecast probability is published and how it has been used in canal advisories, where the Authority has cited a rising probability of a severe El Nino as the stated reason for draft reductions.