Harvest Weather Hinges on Start of La Niña
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The hot summer predicted by most spring weather models didn’t happen in the Corn Belt until August because La Niña has not yet developed in the Pacific Ocean.
The global atmospheric circulation remains in the neutral position after leaving El Niño (warmer-than-average Pacific water temp-atmosphere coupling). The arrival of cooler-than-average La Niña pattern (the opposite phases of the El Niño/Southern Oscillation, or ENSO) has yet to occur, but is forecast to happen in September or October. For a deeper dive, follow the ENSO blog.
“The colder water in the Pacific has remained just below the surface since early June and hasn’t risen to form a La Niña pattern yet,” says John Baranick, DTN meteorologist. “It’s unexpected, as all the signs exist, but it just hasn’t happened yet.” Current computer climate models predict a 70% chance that La Nina will develop during the August-October timeframe.
Corn Belt Looks Good
As of this late August writing, Baranick believes the bulk of the Corn Belt is in good shape heading into a September. The active weather patterns have provided good soil moisture across most Midwestern states, and excessive amounts in the Dakotas and Minnesota, where crop development remains behind due to late planting.
The usual mid- to late-summer soil moisture concerns exist in only a few pockets in the eastern Corn Belt states of Ohio, Kentucky, and south into Tennessee, he says. Issues with severe weather have been scattered throughout this active pattern. A July 15 derecho with 80 to 100 mph winds moved through Iowa, northern Illinois and northern Indiana. Heavy storms, hail and winds have also rolled through parts of Wisconsin, the Dakotas, Nebraska, Kansas and Missouri.
Fortunately, the dry weather is holding off, thanks to a delayed La Niña.
“We’ll continue to get some precipitation chances moving through the Corn Belt, but trends are for a drier-than-normal September,” Baranick says, “which could impact grain fill for corn and soybeans.”
Forecast for a Dry Harvest
When the developing La Niña occurs, DTN is forecasting a drier and warmer fall season leading into harvest. “Heat stress is usually lessened in September, depending on whether there’s enough moisture to finish out the crop or not,” Baranick says. “Currently, we’re looking at below-normal precipitation during September.”
October and November are also typically warmer under La Niña. Baranick cites that two La Niña seasons that fall high on the analog list, 2012 and 2020, both having a cool spell that adds potential risk for an early frost in October. This frost could become more significant for late-planted acres in the Dakotas and Minnesota.
The one caveat that could change this entire forecast is if La Niña is delayed beyond the fall. “This would be an unprecedented delay if we got into winter season without going into La Niña, just because of how warm El Niño was last year,” Baranick says. “But if it happens, we expect a lot more variability in both temperature and precipitation. We could end up with areas that get cold and wet during the fall, making it difficult to harvest.”
Another potential issue is a more active tropical storm season forecast to increase by mid-August and beyond. That doesn’t mean tropical cyclones will impact Corn Belt weather, but Baranick says DTN will watch the hurricane center closely.
Global Weather Woes
Looking at weather beyond the Corn Belt that could impact grain prices, Baranick is watching the Black Sea region, Europe and South America. Ukraine and western Russia have been experiencing a hot, dry stretch going back to February, which caused a spike in wheat prices.
“Poor growing conditions and frequent high temperatures could impact corn, soybeans, sunflowers and other crops in Ukraine and western Russia,” Baranick says. “We’re also seeing issues with winter wheat and now corn in Germany and France, which have been wet for a long time but have become drier recently.”
If and when La Niña finally happens, he says, the September planting season in Brazil and Argentina could get hot and dry, similar to the 2020 to 2023 seasons. Australian wheat remains in good shape, which could improve more with rains from a developing La Niña.
Content provided by DTN/The Progressive Farmer
Hear more about the harvest weather outlook and the impact on weed control from Baranick and Jeff Moon, Corteva Agriscience market development specialist.
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