Weather Tight Rope

Forecasters weigh in on this summer's outlook in a game of high-stakes poker.

The stakes are high and the margin for error is ever so small. Both corn and soybeans must have normal yields this year to meet anticipated demand in the marketing year that begins September 1. A cool wet start to the growing season tipped the odds against this year's crops, but where do we go from here?

The good news for this year's crops is that La Nina is weakening faster than models previously predicted. A period of rapid warming of cool sea surface temperatures in the equatorial Pacific earlier this spring now has the current La Nina in the weak category, with models suggesting continuation of a neutral to weak phase through the growing season.

CropCast expects this declining La Nina to reduce the stress on crops in the Midwest Corn Belt this summer, with only regional dryness focused on northwestern portions of the belt. Warmer than normal temperatures are expected in western areas of the belt, but they should be less intense than previous forecasts.

NOAA's forecast model for sea surface temperatures features a continued warming of the Pacific into an El Nino phase, which intensifies heat over the northwestern Midwest. However, this model is among the more extreme of the 20 models that forecast sea surface temperatures and is not currently looked at with a great deal of confidence.

The U.S. Climate Prediction Service expects high pressure to build over the Rocky Mountains, keeping heat primarily west of the Plains. However, the pattern is expected to focus dryness over the Pacific Northwest and the northern Plains, stretching northward to the Canadian Prairies. Even so, they note that the area of high pressure could shift a bit further east, threatening the western Corn Belt, if La Nina sustains its strength a bit longer than expected. Either way, it leaves much of the spring wheat belt on the borderline of adverse growing conditions.

Statistics stacked against this year's crops

But Elwynn Taylor, Professor of Ag Meteorology at Iowa State, isn't convinced. Taylor shared his thoughts in an exclusive interview with Farm Futures, reflecting considerable concerns about the coming growing season. Taylor points first to La Nina, which gives 72% odds of a below-trend yield if La Nina hangs on through July. Fortunately, the odds improve somewhat if La Nina experiences a pre-mature death, which appears to be happening. As such, he currently places those odds at somewhere around 30%.

Next, Taylor points the historical tendency for droughts to hit the Midwest following a major drought in South Carolina, which was certainly the case in 2007. The Midwest Corn Belt experienced 17 major droughts over the past 100 years and 16 of them were preceded by a significant drought in South Carolina. Only twice over the past century did South Carolina experience a drought without a major Midwest drought following the next year.

Third, Taylor points to the statistical occurrence of droughts in the Midwest. The average time between droughts in the Midwest is 18.6 years. The most recent drought was in 1988. Taylor indicates that the longest period without a major drought over the past 800 years was 23 years. The last time that all three of the above factors came together was in 1988.

On a positive note, Taylor points to good soil moisture levels across the Midwest. However, he warns that wet soils at planting can be a problem if the summer turns off dry. That happened belt wide in 1947, and again in 1983.

Sea surface temperatures in the north Pacific are running above normal, as they have for much of the past eight years. This tends to result in drier weather for Colorado. That's significant, according to Taylor, because conditions in Colorado have a strong influence on conditions further to the east, including areas of Texas west of Ft. Worth, much of Oklahoma, Kansas, North Dakota, part of South Dakota, northwestern Missouri and western Iowa.

An apparent early weakening of La Nina gives some hope for crops in a year when everything goes right. In fact, the U.S. Climate Prediction Center expects the core of the Midwest to be cool and west through much of the month of June, favoring good crop development. But this year's crops will also be fighting history, which suggests that the statistical odds are stacked against them. That places increased importance on updated long-range weather forecasts as we go through the season, as well as on USDA's Monday afternoon crop progress and condition reports. Timely updates on both will be provided throughout the growing season here at


TAGS: USDA Soybean
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