Another month of fighting dryness on the horizon
July 16, 2012
by Drew Lerner
June was an unusually hot and dry month for many key crop areas across the United States stressing many crops in the lower and eastern U.S. Midwest, lower Mississippi River Basin Delta and southeastern states. World Weather, Inc. anticipates another month of fighting dryness during July, despite less oppressive heat in the eastern Midwest and some increase in rainfall frequency. The heart of the most stressful conditions will shift to the region from southeastern Nebraska, southwestern Iowa, Missouri and southwestern Illinois to West Texas.
June will go into the record books as another unusually dry and warm month for the heart of U.S. crop areas with rainfall well below half of normal for most of the Midwest, the lower Mississippi River Basin and interior southeastern states. Many reports of less than 25% of normal rain were received from southern Wisconsin, parts of Michigan and many locations scattered across Illinois, Indiana, Kentucky and Tennessee. The only wetter-than-usual areas were limited to pockets across the upper Midwest and from northeastern Kansas into southwestern Iowa. The only notable areas of above average rainfall were limited to Maine, northern Florida, extreme southern Georgia and in the Pacific Northwest.
Onset of crop moisture stress
The heat and dryness brought on considerable crop moisture stress and cost producers and farmers some significant yield because of the moisture stress that occurred while crops were reproducing.
A high pressure ridge will continue to move around in the middle of the United States during the month of July. However, its presence will be less persistent in the eastern Midwest and much more common in the U.S. Plains and western Corn Belt. Crops will benefit from the changes, but the changes likely will prove to be too little, too late to save some of the corn crop.
Rainfall during the month of July will increase, but many Midwestern locations that reported 15% to 50% of normal rainfall in June may get 50% to 75% of normal rain this month. That will be a welcome improvement, but with moisture deficits from normal being significantly great it will be almost impossible for crops to get enough rain to eliminate moisture stress completely.
Normal rainfall in any summer season is often too little to counter evaporation. That is especially true of July and August when temperatures are traditionally warm enough to maintain strong drying rates between thunderstorms. It would take an unusually cool summer to allow crops to develop without further stress in the rainfall environment that is predicted for the next few weeks. The only way conditions would change greatly would be if a tropical cyclone were to come northward out of the Gulf of Mexico and that is not very likely.
Temperatures in July will be warmer than usual in the central U.S. and into parts of the lower and eastern Midwest, as well as a part of the northern Delta. The only cooler bias to weather in crop areas will be in a part of Michigan, Wisconsin and Ohio, but only for short periods of time. Cooler conditions will impact the northeastern states.
Wetter-than-usual biased conditions are expected in the southeastern corner of the nation and in the northern Plains.
Elsewhere in the world
Atmospheric and Oceanic conditions in the eastern equatorial Pacific Ocean are changing in support of developing El Niño conditions. The phenomenon will change world weather patterns as it evolves. One of the changes in North America expected in late July and more likely in August will be greater rainfall. A boost in precipitation and some cooling will impact the north-central U.S. (including the upper Midwest) during the month.
In the meantime, relief from dryness has occurred in east-central China’s drought stricken region ending concern about production cuts in that nation’s grain and oilseed production region.
Dryness is still being closely monitored in India, especially now that it looks as though El Niño will develop. El Niño usually means below average rainfall in India, Indonesia, Malaysia and eastern Australia and each of these crop areas will be closely monitored for possible dryness issues a little later this year. The impact might be significant on wheat production from eastern Australia and palm oil, sugar, rice and many herb and spice production from Indonesia and Malaysia later this year.