While it is too early predict its intensity or impact on crops, meteorologists said, a shift towards a mild occurrence of La Nina, when surface ocean waters cool off the tropical west coast of South America, is looming.
“The vast majority of weather models are pointing towards a weak La Nina in the second half of the year or towards the last quarter. One out of maybe 25 weather models is showing a strong La Nina,” said Chris Hyde, a meteorologist at US-based Maxar.
Last year’s El Nino, which followed three La Nina years, saw hot and dry weather in Asia and heavier rains in parts of the Americas that boosted farm output prospects in Argentina and the southern US Plains.
India, the world’s biggest rice supplier, restricted exports of the staple following a poor monsoon, while wheat output in No.2 exporter Australia took a hit. Palm oil plantations and rice farms in Southeast Asia received less than normal rains.
La Nina could reverse the situation.
“Hypothetically, La Nina is obviously very good for Aussie crops, but it really depends on when the rain falls or doesn’t fall,” said Ole Houe, director of advisory services at agriculture brokerage IKON Commodities in Sydney.
“Rain needs to fall prior to planting so there is good subsoil moisture or regularly during the growing season.”
In rice and palm oil-producing Southeast Asian countries, wet weather could boost yields, analysts said, while a normal Indian monsoon would boost production and farm incomes.
“Maybe for southern India there could be a little bit of lingering dryness but for the vast majority of the country – the centre and the north in particular – slightly above normal rains,” Maxar’s Hyde said.
US climatologists predict La Nina’s arrival in late summer or early fall.
“As we get into the growing season, our precipitation across the Corn Belt is primarily thunderstorm-driven,” said Iowa state climatologist Justin Glisan. “If La Nina kicks in late September, early October, that would be beneficial.”
La Nina’s onset in July-September could cause a dry autumn in the Corn Belt, benefiting US farmers by speeding the harvest, although it could also lower water on Midwest rivers, hampering barge movement, and reduce grazing pastures.
“The expectations are in some cases opposite of what you would see in an El Nino,” said Mark Brusberg, chief meteorologist at the US department of agriculture.
The US national weather service’s climate prediction centre will issue its monthly weather outlook for the northern hemisphere on Thursday, and the Japan weather bureau’s El Nino/La Nina forecast is scheduled for Friday.