The Trend Toward La Nina Is Impressive

First Tropical Storm of the Season (“Arthur”) Likely This Weekend
05/15/2020, 9:14 am EDT
Cool Waters = Cool Climate Bias
05/25/2020, 12:03 pm EDT
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Highlight: The trend toward La Nina is impressive.

Fig. 1: The 12-week Nino SSTA tracker indicates a sudden turn toward La Nina in the Nino34 SSTA.

Discussion: Since late April the East Pacific equatorial region has suddenly trended cooler both at the surface and especially subsurface indicating La Nina risk is increasing for summer/autumn 2020. The Nino34 SSTA region in the east-central equatorial Pacific is the lead indicator of ENSO phase and trending quickly toward the La Nina threshold (Fig. 1). The Nino34 region is broadly cool now (Fig. 2) and has cooled by a whopping 1C the past 30 days (Fig. 3). The subsurface temperatures in the equatorial East Pacific (Fig. 4) is impressive and certainly supports surface cooling into early meteorological summer. Forecast models indicate potential for La Nina in the AUG/SEP/OCT timeframe. The current rate of cooling indicates La Nina could develop in July.

Fig. 2: The Nino34 SSTA is cooling and approaching the La Nina threshold.

Fig. 3: The Nino34 SSTA has cooled a whopping 0.97C in the last 30 days.

Fig. 4: The subsurface equatorial East Pacific temperature anomalies are becoming boldly cool and supportive of La Nina ahead.