A La Nina event is quickly weakening in the Pacific, and an upcoming westerly wind burst is likely to restore ENSO neutral conditions by early May. Our ENSO Whisperer April output forecasts that cool-neutral conditions are most likely to persist into the summer months, but redevelopment of a weak La Nina or emergence of a weak El Nino are both realistic possibilities based on both our modeling and current conditions in the Pacific.
A moderate La Nina is ongoing in the Pacific. While the conditions in the Northern Hemisphere do not reflect the typical Nina winter, the ocean-atmosphere feedback cycles in the global Tropics are well established. WeatherTiger’s ENSO Whisperer January output is mostly unchanged from the previous several runs.
WeatherTiger’s ENSO Whisperer September output is a little more aggressive with La Nina strength than previous runs, but has not changed in terms of the maintenance of moderate La Nina into early 2021. Model confidence remains high through the forecast period.
The eastern Pacific remained cold in July, while the central Pacific finally began to trend steadily cooler over the course of the month. WeatherTiger’s ENSO Whisperer August output is a little faster to cross the threshold of formal La Nina, showing a 75% chance of -ENSO conditions by September.
WeatherTiger’s ENSO Whisperer July output is a little slower to cross the threshold of formal La Nina, showing the Pacific remaining in cool-neutral conditions through September and developing a moderate La Nina in the fall. However, the earlier development of La Nina is well within the forecast probabilities.
WeatherTiger’s ENSO Whisperer June output is both quicker with La Niña development and more powerful with its eventual intensity. Our model suggests that an official Niña is favored to develop in August or September, with more cooling through fall. Confidence in this forecast is notably higher than last month.
The Pacific has cooled slightly since April, with more rapid cooling beneath the surface indicative of trends into summer. Overall, global circulation patterns continue to reflect ENSO neutral conditions, albeit with a stronger than normal subtropical jet in the eastern Pacific. WeatherTiger’s ENSO Whisperer output for May is a bit more hedged than last month’s on the potential for late summer or fall La Niña development. Our model suggests that observed cooling will persist into mid-summer, followed by an extended period of cool-neutral anomalies.
The Pacific has changed little in March and early April, warm-neutral anomalies remaining in place. Overall, global circulation patterns continue to reflect ENSO neutral conditions, with a slight lingering tilt towards Nino-ish influences as reflected by a strong subtropical jet.
The Pacific warmed slightly in November overall, but atmospheric and oceanic conditions still reflect a warm-neutral ENSO state. WeatherTiger’s ENSO Whisperer output expects that ENSO will stay in neutral conditions into early 2020, with El Nino odds increasing a bit into the spring months.
Our model is unchanged in expecting continued ENSO-neutral conditions into early spring 2020.