University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources

July 21, 2006

State climatologist: Little relief expected from hot, dry conditions

Searing heat invaded much of the nation during the past week, with the core of intense heat situated over central South Dakota and north central Nebraska. High temperatures in excess of 115°F were common at numerous locations in South Dakota, with an unofficial report of 120°F at Usta. Chadron and Valentine both reported high temperatures of 113°F on July 15. Much of central, western, and southwestern Nebraska reported high temperatures between 105°F and 110°F during the July 14-16 period.

Dry conditions. . .

and a heatwave contribute to severe drought conditions across much of Nebraska. See this week's map at the National Drought Monitor.
Rangeland conditions continue to be poor at best, and the fire danger has been in the extreme category on a daily basis. One large fire engulfed a four square mile area on the northern edge of Valentine. Until western Nebraska receives significant moisture and temperatures consistently in the 80s or lower, the fire danger will remain in the high to extreme category.

The heat could not have come at a worse time for the corn crop. As of July 9, 27% of the corn crop was in the silk stage and by July 16, 60% had reached the silk stage. Almost the entire crop is expected to have reached the silk stage by July 23. This means that 73% of the corn crop would have been vulnerable to excessive heat during the critical pollination stage.

Field reports indicate that much of the dryland corn crop is exhibiting heat and moisture stress due to a lack of subsoil moisture. The best looking crops are located across portions of east central and southeast Nebraska where localized heavy rains occurred just prior to the onset of 100°F plus temperatures. Although a brief cool down is expected from July 20-24, temperatures will return to the mid to upper 90s as early as July 25.

Model predictions were for midweek rains of 0.50-1.0 inch in central, east central, south central, and southeast Nebraska. Forecast models for July 22-28 place the chance for precipitation at less than 10% on any given day. Based on the latest short-term forecasts, heat and water stress will continue through late August. Mid-range models point to moisture and slightly cooler weather in early August; however, it should be noted that during the past six to eight weeks, these models have consistently projected this scenario and have been consistently wrong. At this time, I have little confidence that a wet trend is in our future.

The latest 30- and 90-day models indicate above normal temperatures for the central United States, including Nebraska. There are equal chances of below normal, normal and above normal precipitation. Predictions for average high temperatures for Nebraska at the beginning of August range from 88°to 91°F, cooling to 80-84°F by late August. Unfortunately, this forecast does not bode well for an already stressed corn crop.

Al Dutcher
State Climatologist, Lincoln

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Copyright 2006 by the University of Nebraska Board of Regents. All rights reserved.
Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.
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