Questions over the stamina of the El Nino weather pattern, and a potential return to La Nina, have emerged in the cocoa sector too after unexpectedly strong rains reached Ivory Coast, the top producing nation.
The El Nino pattern which has been long been forecast typically brings a drier pattern to West Africa, lowering production potential.
El Nino seasons typically see a 2.4% drop in output, equivalent to some 100,000 tonnes, thanks to the impact in the likes of Ivory Coast, besides a dip in Ecuador too, according to International Cocoa Organization research.
However, while clocking "growing fears for the return of a supply deficit" in 2012-13, after two years of surplus, the organisation also clocked the occurrence of strong rainfall in some African producing regions sufficient to stoke concerns for plantation diseases.
Although the US Climate Prediction Center, supported by model forecasts and continued warmth across the Pacific Ocean, is forecasting the occurrence of most likely a weak El Niño… there have been increased threats of black pod disease reported in some African cocoa producing regions following some heavy rains," the ICCO said.
The El Nino, "which started in September 2012 and was expected to persist through December-February 2012-13".
The observation is the latest in a series questioning the status of the weather, as regards the El Nino, with some other observers also clocking conditions which appear more consistent with its counterpart, the La Nina.
Gail Martell, at Martell Crop Projections, said that while many indicators in fact signalled neutral conditions, "a La Nina signal has emerged in the US" in precipitation extremes.
"October-to-November rainfall has been virtually absent in the southern third of the US, intensifying drought, while heavy rains have pounded the Pacific Northwest in recent weeks. Colder temperatures have developed in the Midwest.
"These developments suggest a La Niña influence may be in play."
In South America, meteorological service Metsul has said that some of their long-term models are showing a potential cooling in Pacific water temperatures sufficient to prompt a mild La Nina early in 2013.
"If that occurred, it could result in deteriorating crop prospects for southern Brazil because neutral conditions or a La Nina generally increases the chances of dryer than normal weather in southern Brazil," Michael Cordonnier, at Soybean and Corn Advisor, said.
The concern for Brazilian corn was that, until rains the last couple of days, the southern states of Brazil had gone without rainfall for some three weeks, with even the latest round of precipitation "not enough to recharge soil moisture levels".
The concern is that, with December the key month for southern Brazilian states, responsible for more than half Brazil's main corn crop, "if we not get the moisture back, and temperatures go back up, we are going to have a lot of corn during pollination," a poor harbinger for yields.
Indeed, Dr Cordonnier said that he may next week downgrade his forecast for Brazilian corn output in 2012-13 "depending on the forecast".
The El Nino-La Nina spectrum is closely watched because of its impact on world crop production, with many blaming a La Nina for the dry weather which cut crop production this year in the US and South America.
The ICCO's comments came as it ditched ideas of a world cocoa output deficit, of 19,000 tonnes, in 2011-12, saying that the season, which finished in September, produced a surplus of 90,000 tonnes.
The revision reflected in the main higher estimates for world production, thanks to a "late surge in arrivals and purchases" of beans in the top two producing countries, Ghana and Ivory Coast.
However, the organisation flagged a "slow start" to deliveries by farmers in Ghana in 2012-13, in part a hangover from the "heavy selling" towards the end of last season.