Sea surface temperatures (SSTs) are near normal across most of the equatorial Pacific (Figs. 1-2). Conditions are forecast to remain ENSO-neutral through summer 2020, while some outlooks point to a possible La Nina event later in 2020.
Forecast Roundup: On June 9, the Australian Bureau of Meteorology maintained their ENSO outlook at an inactive status. They higlighted that a few models indicate a possible La Niña in 2020, and are monitoring these conditions to determine La Niña watch status. On June 10, the Japanese Meteorological Agency (JMA) maintained its call for a 60-percent chance of ENSO-neutral conditions through summer 2020. On June 11, the NOAA Climate Prediction Center (CPC) issued its ENSO diagnostic discussion with an inactive alert status. The CPC called for a 60-percent chance of ENSO-neutral through summer 2020, and with “roughly equal chances” between ENSO-neutral and La Niña for fall 2020. On June 11, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), noting “model forecasts favor coolish but neutral SST conditions into summer, becoming more strongly below-average, and possibly in weak La Niña territory.” The North American Multi-Model Ensemble (NMME) mean forecast is within the range of neutral, but is projected to move closer to borderline La Niña conditions later in 2020 (dashed black line, Fig. 4).
Summary: The oceans cooled over the past few months, and overall, oceanic and atmospheric conditions were in the range of ENSO-neutral during this period. Most forecasts call for these conditions to remain ENSO-neutral through the summer, but by fall, it is effectively a toss-up between ENSO-neutral and La Niña. ENSO status tends to have a weak relationship with monsoon precipitation (at least in our current understanding). La Niña is associated with suppressed tropical storm activity in the Pacific during the fall, and drier than normal conditions in the winter.
- Figure 1 - Australian Bureau of Meteorology - bom.gov.au/climate/enso
- Figure 2 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov
- Figure 3 - International Research Institute for Climate and Society - iri.columbia.edu
- Figure 4 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov