North American Drought
The IRI has worked in collaboration with the NOAA Earth System Research Laboratory (ESRL) and Climate Prediction Center (CPC) to develop a set of tools that provide probabilistic forecasts of future Standardized Precipitation Index (SPI) as an indicator of drought for various accumulation periods over the U.S. and Mexico based upon two forecast methodologies.
In addition to the SPI forecast tools, analyses of observed precipitation conditions using monthly SPI are provided, based upon monthly totals from the CPC's global Unified gridded precipitation dataset.