Ag Weather Forum

Rains Bring Crop Development Questions

Mike Palmerino
By  Mike Palmerino , DTN Senior Ag Meteorologist
Heavy rain and below-normal temperatures in the next 10 days may tax the ability of emerged corn and soybeans to maintain their progress. (DTN photo by Pam Smith)

Crop weather trends over the past week have been highly variable. We saw favorable weather for rapid planting of corn and soybeans in the western Midwest over a five-day period from May 11 through May 16. And progress was impressive. Around one-third of both corn and soybean acreage in Iowa was planted last week. Nationwide, both corn and soybean planting progress is now running ahead of normal on this week's report after being behind normal a week ago. Eastern Midwest areas have seen some chances to renew the planting effort after wet conditions in the past week.

The upcoming seven-to-10 day timeframe does offer some challenges for crop conditions and development. The pattern turns wet to very wet in the next week in the Midwest. Temperatures are likely to generally be below normal, with rainfall at or greater than normal. This may lead to slow growth of crops and possibly some yellowing of fields in areas where nutrients leach out of the soil. In addition, discussion of the need to consider replanting is going on, notably in the eastern Midwest.

Winter wheat continues to show an uncertain outlook. We have not seen much of a recovery in winter wheat crop ratings in the southern Plains with the exception of Nebraska. The most favorable pattern for recovery from the snow and cold of a few weeks ago would be warm and dry conditions.

However, that is not the case with generally below-normal temperatures and near to above-normal rainfall in the forecast over the next week to 10 days. The cool and wet pattern no longer benefits the wheat crop, and will make it more difficult for damaged wheat to recover from the snowstorm and cold at the end of April. Disease pressure and reduction of crop quality are very possible as the crop matures.

Looking farther ahead into the heart of the summer season: Our latest calculation of the sea surface temperature departure in the eastern equatorial Pacific Ocean for the first half of May is 1.2 degrees Celsius above normal. This is up from the 0.8 C above normal value observed during the month of April. It appears that an event described as a "coastal" El Nino along the western South America coast earlier this year rapidly faded during April. However, the sea surface temperatures are now warming over central portions of the eastern Pacific. This is the area that normally defines the El Nino/La Nina region. We may now be seeing the development of a more classic El Nino as we head into summer. If this is the case, we would not expect to see any significant drought issues developing in the Midwest.

Michael Palmerino can be reached at



To comment, please Log In or Join our Community .