ALERT for significant anomalous heat and dryness emerges across West and Central Europe during the second half of June. To best illustrate the threat, the AIFS ENS is utilized. AIFS ENS has generally been the top or near the top model for skill scores during the past 30 days.

Traditional measurements of ENSO phase indicated El Nino onset during early Q2/2026. However, the new relative operational Nino index (RONI) is (now) used to determine ENSO strength and forecasts. Using RONI, NOAA identifies the presence of El Nino beginning in June. Dynamic models continue to forecast a potential record strength oceanic El Nino likely due to the immense upper ocean heat rivaling the 1997-98 El Nino as most intense on record. However, using a RONI analog, the ENSO climate may be less impressive and is followed by La Nina returning next year.

The immense Mediterranean Sea marine heatwave is expanding eastward which supports positioning of the upper-level high pressure ridge shifting eastward as indicated by the CFS V2 week 2-4 outlook.

A glimpse at historical climate pattern across North America, Europe, South America, and Australia for DEC/JAN/FEB during strong El Nino is reviewed. Only 2 strong El Nino’s have occurred during the past 2 years. The most recent (2015-16) is likely more representative of DEC/JAN/FEB 2026-27 due to the occurrence of strong El Nino during accelerated global oceanic warming.