Multivariate ENSO Index - MEI
North Atlantic Oscillation - NAO
The Multivariate ENSO Index (MEI) is used to characterize ENSO phases and strength. High positive (red) values indicate El Niño, while negative (blue) values indicate La Niña phases (read more) Strong positive (red) phases of the North Atlantic Oscillation (NAO) tend to be associated with above-average temperatures in the eastern United States while strong negative phases tend to be associated with the number of daily cold extremes during the winter (read more)