The IRI probabilistic seasonal climate forecast product is based on a re-calibration of model output from the U.S. National Oceanographic and Atmospheric Administration (NOAA)’s North American Multi-Model Ensemble Project (NMME). This includes the ensemble seasonal prediction systems of NOAA’s National Centers for Environmental Prediction, Environment and Climate Change Canada, NOAA/Geophysical Fluid Dynamics Laboratory, NASA, NCAR
and COLA/University of Miami. The output from each NMME model is
re-calibrated prior to multi-model ensembling to form reliable
probability forecasts. The forecasts are now presented on a 1-degree
latitude-longitude grid.