The equatorial Pacific is in a neutral state, with atmospheric measures of ENSO divided between Niña and Niño-like patterns. WeatherTiger’s proprietary ENSO Whisperer is a little quicker to move the Pacific towards a weak El Niño, with the development of a weak or moderate +ENSO over the fall and winter of 2018 continues to be our preferred forecast solution.
El Niño Outlooks
Observations and model data support an inactive ENSO pattern for 3-4 months, with WeatherTiger’s proprietary ENSO Whisperer model continuing to favor the development of a weak +ENSO event early in the fall.
Observations and model data support at most a neutral-positive ENSO state through the summer. WeatherTiger’s proprietary ENSO Whisperer model has shifted cooler in the medium-range to reflect increased chances of continued neutral conditions as the North American planting and growing seasons approach.
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.
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.