The Evaporative Demand Drought Index (EDDI) examines how anomalous the atmospheric evaporation demand is for a given location and across a time period of interest according to NOAA. Atmospheric evaporation demand is often referred to as “the thirst of the atmosphere”. The timescale of this index can vary to capture drying dynamics that themselves operate at different timescales.

Dr. Nate Mantua, PDO Expert at the NOAA/NMFS Southwest Fisheries Science Center reports that the March 2021 Pacific decadal oscillation index was -1.17 which represents moderate-to-strong cool phase. During March the -PDO regime present since early last year intensified to the strongest level during this 14-15 month-long cool regime.