A weak La Niña event continues in the equatorial Pacific, reduced in intensity since last month but still not having weakened back into ENSO neutral conditions. WeatherTiger’s March modeling continues to suggest that any transition to an El Nino will not be rapid, and neutral conditions are favored through much of the summer. This indicates that ENSO is less likely to be a major factor this U.S. growing season.
El Niño Outlooks
An eastern Pacific-based moderate La Niña event continues but has very likely peaked in intensity in December/January and is starting to weaken. WeatherTiger’s February modeling shifts slightly in the direction of a potential summer El Niño from our previous several runs.
WeatherTiger’s January modeling is little changed from our previous several runs, continuing to suggest that La Niña peaks in January and begins to moderate in February, with neutral-negative conditions in March and April and true neutral conditions in May and June.
The equatorial Pacific remains on the borderline between neutral-negative conditions and a weak La Niña. WeatherTiger’s November modeling again trended modestly cooler this month, with chances of at least weak La Niña in place by year’s end now well over 75%.
WeatherTiger’s October modeling has trended modestly cooler this month, with chances of at least a weak La Niña developing by December rising to well over 50%. La Niña is now likely to be strong enough to influence growing season precipitation distribution in South America, and potentially the U.S. winter pattern as well.
The equatorial Pacific has cooled quite a bit in the last month due to a strong surge in easterly trade winds, and ENSO is beginning to tip into a weak La Niña state.
WeatherTiger’s August modeling shows a solidly neutral ENSO state through year’s end. Major changes to this overall outlook are not expected in the next 3-6 months, as there are seldom large shifts in the Pacific in the latter half of the year.
The latest dynamical ENSO models are showing a strong consensus for continued warm-neutral conditions over the rest of 2017. This is in good agreement with WeatherTiger’s July modeling, which shows a solidly neutral state through year’s end.
After calling for at least moderate El Niño to develop by the summer throughout the spring, dynamical models are still backpedaling in favor of projecting a continuation of warm-neutral conditions. WeatherTiger’s June modeling is cooler again showing solid neutral conditions through year’s end.
The equatorial Pacific remains in neutral ENSO conditions, showing neither a La Niña nor an El Niño state. The uncertainty regarding the evolution of ENSO over the next six months is starting to decrease as evidence mounts that ENSO will remain in a neutral-positive state or only a very weak, marginal El Niño will develop in the next six months.