Today’s guest post is by Dr. Dennis Todey, USDA Midwest Climate Hub Director, with timely climate information for harvest 2017.
The latter part of summer presented a marked change from early summer. Cooler than average weather predominated over Iowa and the eastern Midwest since late July. This is sharp contrast to the June warmth and warm late winter/early spring. These conditions and new outlooks present some different issues for Iowa concerning crop development and moisture as we enter the fall.
The warm early season exacerbated the dry early season in much of Iowa leading to increased drought conditions. The warm temperatures also helped push crop development that had been slowed because of some delayed planting and cool late spring temperatures. The recent coolness has been a benefit for corn and beans allowing some better grain fill. However, the lack of Growing Degree Days is a problem for corn development, which is as much as 2-3 weeks behind in places in the state. The first fall freeze will need to hold off until near average or later to alleviate potential freeze issues on crops.
Conditions in parts of the state have flipped from early to late summer. Much drier than average conditions predominated much of the south to northwest parts of Iowa while the northeast to east central were moist to wet. Over the last 30 days rainfall has helped ease drought conditions in northwest Iowa while the eastern part of the state has dried showing changes in the US Drought Monitor. Most of the southern part of the state is still in some level of drought.
Continued Dry Conditions
Dry conditions are likely to continue to affect much of the state into the fall given the current US Drought Monitor status. This is a positive for fall agricultural field work and completion of construction in the state because of the reduced chances for muddy conditions. But for dry areas impacted by drought, this is not good news (largely central and southern Iowa). Soil moisture recharge in these areas needs to begin in the fall to replenish soil moisture.
Cooler than average temperatures are still likely to impact the state for the balance of September. This will continue to slow crop development and increase the risk of freezing conditions earlier than hoped for many crops. Exact freeze dates will continue to be monitored.
Early Winter Outlook
Winter outlooks are largely impacted by having an El Niño or La Niña. Neither is likely to be affecting the winter outlook. Thus, our ability to say much for the winter is limited. The overall trend over recent years has been toward warmer winters. Thus, the outlook for the winter would lean a little more likely to be warmer. Precipitation chances are largely unknown at this point.