A lot of talk about Super El Nino, but the late summer 2026 upper air pattern is shaped mostly by the influence of strong marine heatwaves (MHW) in the East Pacific and the cooler SSTA zone in-between. Most prominent is Super MHW25A, forming late last year and persisting at record warm levels to date, this warm ocean feature is well-correlated to amplified high pressure centered on the Southwest U.S. and causing this sector of the nation to experience their warmest year on record.

Extremes are evolving in mid-August. Flash drought in a dry climate with excessive heat is underway in the Mid-south U.S. Meanwhile, to the north of the rapidly emerging drought, ring of fire thunderstorms is flooding the Midwest States.

The U.S. population weight CDD forecast indicates a slow decline in anomalous warmth from peak hot week ending August 12th to near normal for the week ending Sep. 2.

Dramatic cooling of SSTA surrounding Northern Europe foreshadows an upper trough bringing a late August pattern change for Europe as an upper trough emerges next week and lasts into late month.