Early Signs Suggest Potential for Fall Moisture
August 24, 2012
As September approaches, producers have been raising questions about whether 2013 will bring a repeat performance of the drought conditions that have brought misery to a significant portion of the U.S. Corn Belt. In all honesty, it is simply too early to make an educated guess. The next three months will determine whether we begin the drought recovery process and have a reasonable chance of building enough soil moisture to elevate our chances of producing normal crops during 2013.
I am seeing hope in some signs in the upper air patterns that simply didn’t exist for much of the past three months. During the past two weeks, most of Nebraska has experienced below normal temperatures as upper air troughs have moved southeast from the northern Rockies, regularly bringing cold fronts through the state. Unfortunately, the cooler conditions have not resulted in widespread precipitation across the state.
As this upper air ridge buckles when these troughs approach the northern High Plains, monsoon moisture has been pulled northward into the central Rockies, helping form scattered pockets of thunderstorms across the state. With cooler air developing aloft, a more unstable atmosphere is created as cold fronts approach the region. For much of the summer, the atmosphere under the high pressure ridge was just too warm aloft and convection was suppressed.
If these troughs begin to dig further southward as September progresses, we should begin to see more widespread moisture events, especially if the monsoon moisture continues to stream into the central Rockies. With wheat planting rapidly approaching, I am hopeful that enough moisture will fall to germinate and establish stands.
Additionally, we generally don’t concentrate on soil moisture recharge until late September because crops are still actively using water. With the amount of silage being cut and corn fields close to harvest, there is the opportunity for an additional month of building soil moisture reserves for the 2013 production season than we would typically see.
In addition, tropical storm Isaac is expected to make landfall near the Alabama-Mississippi coast next Wednesday. The moisture from this system should bring significant moisture to the southeastern U.S. and possibly make it northward into eastern sections of the Corn Belt. There has been a continual westward drift in the consensus storm track the past four days and there is an outside chance that landfall could be as far west as the northeastern coast of Texas.
If this system can deliver two or more inches of moisture across the eastern and central Corn Belt, the resulting surface moisture could affect weather patterns and increase the likelihood of more expansive precipitation patterns across the entire Corn Belt.
Extension State Climatologist