OMAHA (DTN) -- The Northern Hemisphere's winter and Southern Hemisphere's summer both offer potentially stressful weather conditions for corn. As a result, the market is likely to maintain at least a neutral stance toward corn from a weather factor standpoint.

On a large scale, El Nino in the equatorial Pacific -- a feature characterized by warmer-than-normal temperatures and a west-to-east subtropical jet stream component -- promises to be in effect.

"Projections are that this El Nino will be a weak to maybe moderate event," said DTN Ag Meteorologist Mike Palmerino. "The trends this fall have been to both warmer temperatures and a strong west-to-east flow. This leaves us in a situation where it looks like El Nino is a done deal and will continue in some respect through the Northern Hemisphere winter-Southern Hemisphere summer."

That trend would typically mean a dry winter in the northern Midwest, along with above-average rainfall in Argentina in the Southern Hemisphere. But, in Palmerino's view, there are some other large-scale features also influencing the forecast landscape for the upcoming season.

For the Northern Hemisphere, it's upper-atmosphere blocking (high pressure) off the Pacific coast in the higher latitudes. In Argentina, the detail that gets in the way of 100 percent El Nino influence is the lingering presence of the drought pattern that devastated crop production in 2008-09.

"This is a blended El Nino impact," Palmerino said. "In the Northern Hemisphere, I like the idea of colder conditions in the north, with surges of cold air coming out of western Canada into the central and eastern U.S. I also like the idea of a storm track, coming from northern California and the Pacific Northwest, and then dropping southeast into the south-central U.S. and then lifting out northeast."

U.S. CORN HARVEST VULNERABLE

Such a scenario does not favor U.S. corn harvest efforts.

"With this setup, you're talking about potentially significant snows and more vulnerability in terms of crops sitting out in the field," Palmerino said. "The potential is greater going into late November and early December that there could be corn in snow cover again in parts of the Northern and Western Corn Belt."

Another troubling aspect to this prospect for more snow is that the U.S. Corn Belt's next spring corn crop could experience delayed planting for the third year in a row.

"If the Midwest winter follows the pattern I think it will, we could certainly be colder, with possibly more snow, and with these trends leading to another round of slow field work in spring 2010," Palmerino said.

BATTLEGROUND CLOSE TO CROP BELT

For Argentina, Palmerino sees a sharp demarcation developing between east and west when it comes to precipitation during the Southern Hemisphere summer.

"The old drought pattern featured more west and southwest flow aloft, which is drier," he said. "That battleground is going to be somewhere close to the main crop belt, between available tropical moisture and the dry slot."

To Palmerino, the areas of greatest concern are the farther-west crop provinces. "They may be just enough in the dry air that the tropical moisture stays north and east of those western areas," he said.

That, in turn, could produce some ill-timed stress for Argentina's corn -- projected to total 13 million metric tons by the Rosario Grain Exchange, slightly above the drought-affected 2008-09 crop, which came in at 12.6 million tons.

"This drier scenario will likely impact corn during pollination," Palmerino said. "The western areas like western Buenos Aires, La Pampa and Cordoba are in line for the greatest dryness potential."

Bryce Anderson can be reached at bryce.Anderson@dtn.com

(ES/AG)

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