A short-lived La Nina is ahead and supported by vast cooling of the subsurface equatorial East Pacific during recent weeks. However, if the warming Northeast Pacific persists in early 2026, the La Nina episode ends, possibly abruptly and the warm waters of the Northeast Pacific spread south possibly causing an El Nino onset middle third of 2026 which could become intense later next year.

Vividly present is the NAWH pattern south of Greenland. Aloft, the cooler water is linked to a summer of 2025 upper trough. The 15-day forecast maintains this pattern. The upper trough forces the subtropical ridge farther south. The ridge is forcing dry air into the subtropics/northern tropics inhibiting tropical cyclone development.

The culprit to North Atlantic tropical cyclone development is too much dry air promoted by a strong subtropical high pressure stretched across the North Atlantic basin whereas the 2020-24 climatology produced low pressure in the tropical/subtropical North Atlantic due to presence of tropical cyclones.

During the past week, the Nino SSTA regions have cooled dramatically. The Nino34 SSTA is -0.49C today, very close to the -0.50C La Nina threshold. Off the northwest coast of South America, the Nino12C chilled rapidly to -0.80C. In the tropical Indian Ocean, the western areas have cooled while the southeast tropics have warmed dramatically signaling a moderate-to-strong negative Indian Ocean dipole (-IOD).