Cool waters in the equatorial Pacific are likely to stay until April, signaling a continuation of the current La Niña weather pattern, according to the most recent National Oceanic and Atmospheric Administration (NOAA) announcement.

In the past, a strong La Niña weather event that extends into summer has been associated with droughts in corn- and soybean-growing regions in the U.S.

“During a La Niña event that lasts into summer, there tends to be less precipitation in the heart of the U.S. Midwest Corn and Soybean Belt,” says Drew Lerner, World Weather, Inc., owner and meteorologist. “During summer, soil moisture conditions naturally dry down, but in a La Niña year, precipitation in late spring and early summer is quite a bit reduced and crop areas tend to dry out faster than in non-La Niña years.”

Although the recent NOAA announcement about La Niña is useful for other weather forecasting purposes, its significance for predicting U.S. corn and soybean production during 2008 is still inconclusive, says Lerner. “The NOAA report only goes out to April,” he explains. “It’s more important to know what will happen with La Niña in May, June and July, and what I’ve been telling people is that this La Niña event will likely last at least through June.”

A prediction for La Niña to last into summer is also a prediction that hot, dry weather may dominate in corn and soybean growing areas, starting in the West and gradually spreading east. “My expectation is that the odds are pretty good we’ll have dryness in the western Corn Belt and the Great Plains this summer,” says Lerner. “Yet, with today’s corn hybrids, a little bit of moisture stress doesn’t always cause significant yield loss. At this point, I anticipate no widespread, serious yield loss across the Midwest, but some reduction is possible if La Niña prevails as anticipated.”

Although recent rains have helped corn and soybean crops in South America, a continuation of La Niña is likely to bring hotter, drier weather to some corn- and soybean-producing areas in that region, as well. “The situation in Argentina doesn’t seem as extreme as it was several weeks ago, but I don’t think they’re done with dry weather,” says Lerner. “Soybeans in Argentina will be in their reproductive stages in February and March, and a return to dry and hot conditions could still have a negative impact on production.”

The current La Niña weather pattern has not created enough dryness to cause significant production problems for soybeans in Brazil up to this point, adds Lerner. However, soybeans in the state of Rio Grand do Sol “will probably get hooked up with dryness in Argentina during February, which could cause yield reductions there, as well.”

For more weather information from World Weather Inc., click here.

For more information on La Niña from NOAA, click here.