September 11, 2009

With widespread below normal temperatures the past two months, much of the Corn Belt will not begin grain harvest before October 1. Of the 18 largest corn producing states, six (Colorado, Michigan, Minnesota, North Dakota, Pennsylvania, and Wisconsin) indicated that 25% or more of their crop hadn=t reached the dough stage by September 7. In addition, nine states (Colorado, Illinois, Indiana, Michigan, Minnesota, North Dakota, Pennsylvania, South Dakota, and Wisconsin) reported that less than 50% of the crop had reached the dent stage.

Based upon the most recent National Agricultural Statistic Service information, Nebraska is far ahead of its eastern and northern counterparts in terms of crop maturity. With normal temperatures for the remainder of the month, we estimate that over 70% of the corn crop will be safe from freeze damage. With normal temperatures and a hard freeze (28ºF or lower), less than 10% of the corn crop appears vulnerable to damage from a hard freeze.

Although cool conditions are anticipated through the September 15, warmer than normal conditions are anticipated to build eastward during the third week of the month. An upper air ridge will dominate much of the western U.S., while cooler than normal temperatures are likely across the central and eastern Corn Belt. This will only delay maturity further and increase the risk of freeze damage to the corn crop.

Weather models do not currently indicate freezing temperatures through September 24; however, cold air is building across northern Canada and could move south by the end of September.

If this storm system does pull cold air southward, the most likely area to be a risk for freeze damage would be across the same areas that have seen the brunt of the cold air the past two months. This includes eastern North Dakota, eastern South Dakota, Minnesota, Wisconsin, Michigan, and the northern third of Iowa. The highest risk for freeze damage in Nebraska would be in the northeastern corner.

Fall Forecast

We are currently experiencing El Nino conditions in the Equatorial Pacific, which is expected to strengthen as fall progresses. This event began building during the early summer as La Nina conditions quickly faded. Since the early 1950s, there have been seven transitions from La Nina to El Nino conditions in the same year, the last in 1974.

During these years, some distinct climate trends were noticed during October and November. When compared to 1971-2000 averages, October temperatures were warmer than normal across the western two-thirds of the state, while precipitation was below normal across the western third of the state. During November, temperatures were below normal across the eastern third of Nebraska, while precipitation was below normal across the entire state.

This trend occurred at least 70% of the time. If it occurs this year, harvest delays due to wet weather should be minimal with the opportunity for natural air drying of this year’s corn crop prior to harvesting.
Al Dutcher
Extension Climatologist