During the past several weeks, a large area of exceptionally warm surface water has developed between 20S and 25S in the South Atlantic Ocean. Initially, the large area of warm sea surface temperature anomalies (SSTA) formed off the Southwest Africa Coast. During the past 30 days the anomalous warmth has surged westward toward the central Brazil Coast.

The rainfall pattern in the tropics across the Pacific Ocean with all El Nino’s since 2000 during AUG/SEP/OCT has produced typical heavy thunderstorm activity and attendant rainfall across the central and east-central Pacific. To compensate, the far western tropical Pacific/Indonesia observes atmospheric subsidence and a dry climate. The vertical air motion difference between the sinking air over Indonesia and rising air near and east of the Dateline drives the El Nino climate. In 2023, the pattern described is not present.

In October 2023, the Nino34 SSTA index was +1.59C which eclipses the +1.50C threshold for strong oceanic El Nino classification. However, the response of the atmospheric climate pattern to the El Nino warming is weak yielding neutral multivariate ENSO index (MEI = +0.3) during SEP/OCT 2023. Preliminary investigation reveals this is a first-time occurrence for a strong oceanic El Nino.

The East Atlantic/Western Russia (EAWR) index is present when a strong trough is located across Europe and north of China while amplified high pressure zones occupy the central North Atlantic and Caspian Sea region. In this pattern, which developed over 1 week ago and is forecast to remain through the next 2 weeks, heavy precipitation stretches across Europe.