A leading catalyst for wet climate forecasts across parts of Brazil during spring 2021 is a projected westward shift of warmer than normal SSTA in the South Atlantic tropics toward the Northeast Brazil coast indicated by most SSTA models. During the past several weeks this previously robust warm SSTA region has trended cooler and is not showing the westward shift as previously indicated. The wet spring forecasts remain but confidence has lowered.

From a climate perspective, the accelerant of anomalous heat which is currently at record levels for California for summer 2021 so far is a semi-permanent upper-level high-pressure ridge present much of the time since 2013 and associated with reginal warming of the northeast Pacific Ocean.

A stronger-than-normal Bermuda high-pressure system is contributing to the lack of relative humidity in the middle atmosphere across the tropical/subtropical North Atlantic basin. The lack of RH in the mid-level atmosphere is well-correlated to lack of tropical cyclone activity since Elsa earlier this month.

Currently, an unusually warm SSTA pattern persists across the central and east Atlantic tropics. The anomalous warm SSTA represents buoyant low-level atmosphere moisture. The IMME (model) forecasts the warm SSTA to surge westward into the northern coast of South America as a La Nina pattern (also) develops by October. The combination of the two SSTA regimes should yield a much-needed wet climate for Brazil.