Fig. 1-2: Global SSTA reveals a dynamic equatorial cool/warm character while multivariate ENSO index is at one of the strongest La Nina signatures on record.
Discussion: The global equatorial SSTA regime has an extremely unusual signature featuring sharp alternating cool/warm zones (Fig. 1) likely contributing to an intense negative phase multivariate ENSO index (Fig. 2) which is representative of a strong La Nina climate despite conventional measures of ENSO phase (Nino34 SSTA) trending toward neutral ENSO. The MEI value for MAY/JUN 2022 was -1.9 which is the strongest negative index in the MEI 1979-2022 climatology with the exception of the second half of 2010 La Nina regime. The difference between the borderline La Nina Nino34 SSTA and intense La Nina MEI is the largest on record. The primary contributor to the intense -MEI is likely the influence on climate of the very warm SSTA in the tropics north of Australia enhancing convection while the relative much cooler waters in the tropical central Pacific suppress convection. A steady robust very La Nina-like positive phase of the southern oscillation index is also supportive of the robust -MEI regime.