Cool Equatorial Pacific Subsurface Lost in July BUT May Regenerate

A classic signature foreshadowing La Nina ahead appeared in APR/MAY in the subsurface equatorial Pacific Ocean. Briefly the cool waters were up-welled to the Nino34 region surface in early June. However, the atmosphere/ocean link-up to produce the proper conditions to initiate La Nina did not happen. For instance, the southern oscillation index was mostly in the negative phase APR/MAY/JUN. So…we’ve lost much of the subsurface cooling in JUN/JUL according to the Australian Bureau of Meteorology analysis. A La Nina Watch remains in-place for 1-3 months from now and there are some signs of La Nina diagnostics returning. Last week the Nino34 SSTA lowered to -0.8C. The SOI in July was in the positive phase and the subsurface cool water near the Dateline is new and expanding. Despite the loss of the APR/MAY cool subsurface there remains a chance of La Nina onset by early in quarter 4 of 2020.