OMAHA (DTN) -- El Nino -- the large-scale weather feature in the equatorial Pacific -- is usually a widespread wintertime precipitation-producer in the Southern Plains, and beneficial for winter wheat areas.

However, the persistent Northern Hemisphere storm track that has been in place for two years shows little sign of changing. That means El Nino's presence could be muted over Texas wheat areas in the 2009-10 winter.

The more-dicey 2009-10 El Nino pattern may also keep moisture supplies short in Argentina's wheat areas, already reduced in size by devastating drought last year.

The result of these two significant effects is a U.S. wintertime wheat market weather factor of neutral, due to the prospects for less-than-desirable production on both sides of the Pacific.

In a normal El Nino event, the combination of warmer-than-normal equatorial Pacific temperatures and a west-to-east subtropical jet stream component results in more generous wintertime precipitation in the southern third of the U.S. -- from south-central Kansas south through Texas, and east to Georgia and Florida. But this El Nino is competing with a dominant North America storm track that shows little sign of budging.

COMBINATION OF EFFECTS

"It's likely that, as we go into winter, you're going to see a combination of effects," said DTN Ag Meteorologist Mike Palmerino. "We'll see an active storm track into the West Coast, but we also likely will see a return to colder weather in Canada. This active El Nino storm track will not come in through central California, but rather through northern California and the Pacific Northwest, and then drop southeast toward the south-central U.S. and lift out from there to the northeast."

The storm track described by Palmerino is oriented farther north than a typical El Nino storm track. Someone gets left out in this setup.

That "someone" is Texas.

"Texas could actually be south of the storm track if this El Nino pattern acts like it looks," Palmerino said. "We would have too much drier air entering from the southwest for Texas to get much in the way of winter moisture, except for the northeastern portion. Central, west and south Texas could struggle."

In 2009, the Texas wheat crop was starved for moisture from winter on through heading. The storm track suggested by Palmerino implies that such a situation could repeat itself.

EL NINO EFFECTS ON ARGENTINA

As for Argentina, El Nino is usually a rainmaker. U.S. Climate Prediction Center analysis of worldwide effects of El Nino during the December-through-February time frame prominently features the eastern half of Argentina as part of a region with "wet" weather conditions relative to normal.

But Palmerino is concerned that the Argentine areas where wheat has been planted are in a still-dry sector of the country -- one which has the potential to, as with Texas, be left out of the rain path.

"We are seeing somewhat of a lingering of the old drought pattern in Argentina featuring more west and southwest flow aloft, which is drier," Palmerino said.

The key to Argentina's weather pattern for wheat will be in La Pampa and southwestern Buenos Aires.

"You've got a real fight going on between the moisture flow from the north and a strong, dry boundary from the south and west," Palmerino said. "That area of La Pampa and southern Buenos Aires may be just enough in the dry air that tropical moisture from the equator stays north and east of those western areas."

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

(ES/AG)

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