The CropProphet forecasts for U.S. corn yield and production have remained nearly steady in the past few weeks, with only minor changes to the overall national outlook (see figures below). The most likely U.S. yield of 174.7 bushels per acre is now almost identical to last year’s outcome, but total production will be several percentage points lower than 2016 owing to reduced acreage; the most likely value for U.S. production is now 14.47 billion bushels.




CropProphet’s county-level forecasts show that corn yields are likely to be significantly above trend in most regions, although there are a few areas of sub-trend yield, most notably in southeastern Iowa and in far western growing areas from Colorado to South Dakota (see figure below). The difficulties in southeastern Iowa are related to drought conditions that have become severe in that part of the state; according to historical data from NOAA, Iowa’s southeastern climate division recorded the driest May-August period since 1988.



Despite the persistent dryness this summer in parts of Iowa and some other areas, satellite measurements of crop vitality indicate excellent conditions in much of the Midwest, and the vegetative health index is almost universally better than normal (see figure below). Based on historical satellite data since 1982, the production-weighted average of the satellite index is at record levels for the time of year, and this supports CropProphet’s assessment of excellent yields.



The September 12 USDA crop production report included a very small upward revision to the USDA estimates of U.S. corn yield and production, and the CropProphet forecasts remain significantly higher than the USDA forecasts (see figure below). Indeed, the discrepancy has grown with the latest report, as the CropProphet U.S. production forecast is now 288 million bushels higher than USDA, compared to 195 million bushels at the time of the August 10 USDA report. According to CropProphet, the nearly steady USDA estimates from recent months have failed to capture the improving trend related to unusually cool weather and an absence of heat stress this summer, and there appears to be a high probability that the USDA estimates will be raised over the next several months as harvest information becomes available.