Ag Weather Forum

Favorable Mid-September Pattern

Mike Palmerino
By  Mike Palmerino , DTN Senior Ag Meteorologist
Little to no rain is forecast over the central and eastern Midwest during the next week, improving conditions for harvest. (DTN graphic)

Crop ratings for the week ended Sunday, September 9, showed mostly steady numbers in the Midwest. The only exceptions were the Illinois corn good-to-excellent total going up by two percentage points and soybeans up by two points in Minnesota and three points in Illinois. Stable to improved ratings throughout the Midwest are likely due to very favorable soil moisture conditions. Even in Missouri and southern Iowa, which have been dry for the past couple of months, topsoil moisture has shown significant improvement.

The weather pattern during the next 6-10 days will feature a strong west-to-east flow, with embedded disturbances across southern Canada and the northern U.S. To the south of this jet, subtropical high pressure will dominate. Moisture associated with Hurricane Florence will be tied up mostly along and off the East Coast, enhancing the prospect for drier conditions in the central U.S. The pattern will be favorable for maturing and early harvesting of Midwest corn and soybeans. Temperatures will average mostly above normal, with rainfall near to below normal. There is no concern about an early freeze in the Midwest during mid-September, as the west to east flow will prevent any significant southward movement of cold air out of Canada. Also, crops are not that vulnerable with development running about a week ahead of normal.

In the Southern Plains, soil moisture levels are quite good due to recent rainfall. However, the pattern does turn hotter and drier over the next ten days. This situation bears watching as winter wheat planting season is just getting underway.

Finally, soybean planting can get underway in central Brazil after September 15, weather permitting. There are indications that some limited shower and thunderstorm activity could develop early next week. However, not enough rain is forecast to suggest that widespread planting will be done. It has turned very hot in central Brazil, which normally occurs prior to the onset of the rainy season. With the lack of any significant El Nino development at this time, we do not expect to see a significant delay in the development of the rainy season this year.

Mike Palmerino can be reached at



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11/17/2018 | 5:37 PM CST