The following content was provided by meteorologist Gail Martell of MartellCropProjections.com:
Drought and Heat Stress in Corn Soybeans and Spring Wheat
A large, stable dome of high pressure has taken control of the North-Central United States, increasing heat and moisture stress. Maximum temperatures in the low-mid 90s F are predicted for the next several days, 6-10 F above normal. Rainfall would be blocked from the heartland by a massive ridge of high pressure, though "ridge rider" thunderstorms are predicted north of the primary grain belt. A line of strong thunderstorms was moving through northern Wisconsin and Michigan this morning.
Over half of U.S. corn and soybeans are in jeopardy from drought and heat stress, and 65% of spring wheat.
Last week, moderate-heavy rains developed in a narrow band of the Upper Midwest. This would provide some relief to corn and soybeans. However, high transpiration from plant leaves may outpace the ability of roots to deliver water to crops. Windy conditions would further accelerate moisture loss from crops.
A massive ridge of high pressure will dominate north central United States and southern Canada this week, bounded by troughs of low pressure on the Pacific and Atlantic coasts. This is a stable pattern. However, the GFS model anticipates a westward shift in the heat dome late Thursday-Friday, opening the door for showers in the Great Lakes area.
Slow Developing Crops, Increasing Moisture Stress
Planting delays and summer coolness, previously, has placed a higher fraction of Midwest crops at risk for drought stress. United States corn "denting" August 18th was only 11% under way, among the slowest rates on record. Iowa soybeans setting- and filling pods were 2 weeks behind the normal pace. The Pro Farmer Midwest Crop Tour last week found northern crop development to be behind normal, across the board, including also Minnesota and South Dakota. As resident of southern Wisconsin, I can confirm corn and soybeans are under severe moisture stress here also.
The heat wave predicted this week in the Upper Midwest would be a mixed blessing, spurring crop development, but at the same time increasing moisture stress.