Ag Weather Forum

Stormy Finish to August

John Baranick
By  John Baranick , DTN Meteorologist
couple of strong storms will move across the country through the end of the month, along with remnants of Hurricane Laura across the Deep South and Mid-Atlantic. (DTN graphic)

Crop ratings slipped again last week. As growers in Iowa continue to assess damage from the derecho that moved through two weeks ago combined with mostly dry weather, crop ratings took significant hits. Iowa's corn rated good to excellent totaled just 50% as of Aug. 23. That is down from a total of 77% rated either good or excellent just four weeks ago. Indeed, most states had ratings decline due to recent dryness; the overall good-to-excellent ratings on corn were down five percentage points and soybeans were down 3 percentage points from last week. It should be noted, however, that ratings for both corn and soybeans are beating the 2019 season at this same time. This is especially true in soybeans where the 2020 good-to-excellent rating total is 14 percentage points higher than 2019. Corn ratings are 7 points higher than at this same time last year.

Dryness and storm damage in August have perhaps pulled back on the record crop forecast by USDA and several private firms; still, conditions are still quite high as crops are starting to mature. Forty-four percent of the corn is estimated to be dented and 5% mature. Soybeans have almost completely entered pod setting and 4% have already dropped leaves.

Rainfall is not going to cause dramatic increases in corn and soybean ratings from here on out. And that is too bad. The weather pattern is turning more active to finish August. A system will move across northern areas Aug. 27-29 with widespread moderate showers from the Northern Plains through the northern Midwest. Rainfall amounts over 1 inch are likely to be found from the Dakotas through the Great Lakes. This comes ahead of Hurricane Laura, whose remnants will move up the Mississippi Valley Aug. 27-28 before hanging a quick right through the Mid-Atlantic Aug. 29-30 ahead of the front. Rainfall along its path is expected to be extreme, as is typical with a tropical cyclone. Widespread 4-6 inches and locally heavier can be expected right along the track of the system with bands of more moderate rain over the Delta and Southeast.

Keeping the pattern active, another system is expected to move into the Plains Aug. 30 and then across the Midwest Aug. 31-Sept. 1. More widespread moderate to heavy rainfall is expected across most areas east of the Rockies from this system. A piece of the system over the Southern Plains may continue heavy rainfall into the early parts of September as well.

Overall, the rainfall will be welcome to immature crops, but is generally too late to cause much of a benefit. And some areas are likely going to wish the rain away. The heavier showers will delay harvest for spring wheat in the Northern Plains. And gusty winds from the weekend storm could cause some damage and lodging to stands. With more of the crop reaching maturity in the Delta and Southeast, the heavy rainfall may cause flooding damage and subsequent quality issues. Excellent conditions that started the growing season have continually gotten worse over the year, though the effects have been very gradual for most areas.

John Baranick can be reached at


To comment, please Log In or Join our Community .