Much needed rainfall across most of the state limited Iowa’s farmers to 4.4 days suitable for fieldwork during the week ending Aug 29., 2021, according to the USDA, National Agricultural Statistics Service. Field activities included harvesting hay, oats and corn silage. Producers were getting ready for row crop harvest with repairs to equipment and bins.
Topsoil moisture levels across Iowa rated 14 percent very short, 30 percent short, 52 percent adequate and 4 percent surplus. Topsoil moisture ratings in west central Iowa were 17 percent very short, 34 percent short, and 49 percent adequate.
Subsoil moisture levels statewide rated 20 percent very short, 41 percent short, 38 percent adequate and 1 percent surplus. Ratings in west central Iowa were 29 percent very short, 43 percent short, and 28 percent adequate.
Corn in or beyond the dough stage reached 95 percent, one week ahead of the 5-year average. Sixty-six percent of the corn crop has reached the dent stage or beyond, four days ahead of normal. Six percent of corn has reached maturity. Iowa’s corn condition rated 58 percent good to excellent. Wind and heavy rain damaged some corn and soybean fields in north central, northeast and southeast Iowa.
Soybeans coloring or beyond reached 18 percent, two days ahead of the 5-year average. There were scattered reports of soybeans dropping leaves. Soybean condition was rated 60 percent good to excellent. Oats for grain harvest is virtually complete at 99 percent.
The third cutting of alfalfa hay reached 79 percent complete, two days ahead of the 5-year average. Pasture condition was rated 31 percent good to excellent. The week’s rains helped pastures show improvement as they greened up in some areas.
Weather Summary provided by Justin Glisan, Ph.D., State Climatologist, Iowa Department of Agriculture and Land Stewardship – A remarkable shift in the storm track across the Midwest brought several days of heavy rainfall and severe weather over northern Iowa. Rain totals topped four to ten inches above normal at multiple stations. Beneficial rains fell across much of the severe to extreme drought region. Unseasonable warmth was also observed statewide during the reporting period with positive departures of eight to twelve degrees in southern Iowa. The statewide average temperature was 77.1 degrees, 5.7 degrees above normal.
Winds shifted to a southeasterly direction Sunday afternoon, Aug. 22, under generally clear skies with highs in the upper 70s and low 80s. Conditions were cooler in northwest Iowa where isolated thunderstorms formed and moved east. An upper-level weather disturbance pushed through the state overnight into the very early morning hours on Monday, firing a line of thunderstorms from central Iowa into the northeast corner. The complex turned southeast and pushed out of eastern Iowa before noon leaving behind rain total above 0.50 inch for many stations in the northeast; more than 20 stations reported an inch or more with Fayette (Fayette County) observing 1.90 inches.
Tuesday, Aug. 24, began an active stretch of days as the first of several rounds of showers and thunderstorms impacted Iowa. A line of strong thunderstorms formed during the early afternoon over the state’s northern half as an intense squall line developed in northeastern Iowa. High humidity and temperatures in the upper 80s and low 90s fed atmospheric instability. Several storms turned severe into the evening hours with widespread reports of severe straight-line winds causing crop and isolated structural damage; 70 mph winds were observed from Hazelton (Buchanan County) to Dyersville (Dubuque County). Additional thunderstorms, some strong to severe, popped up in southwestern Iowa after midnight producing locally heavy downpours; thunderstorms reformed in southeastern Iowa as well.
Rain totals reported at 7 am on Wednesday, Aug. 25, were highest in east central Iowa with the northwestern stations missing a majority of the rain. Two Iowa County stations, North English and Williamsburg, measured 3.08 inches and 3.45 inches, respectively. Widespread totals of 0.25 inch to near an inch were observed. Daytime highs returned to the mid to upper 80s with 90-degree readings southwest.
Overnight lows Thursday dropped into the mid-60s and low 70s in western Iowa as a complex of thunderstorms pushed over the Iowa-Nebraska border. The line expanded as it crossed Iowa through the afternoon.
Two additional lines of thunderstorms fired across a stationary front draped over northern Iowa later in the evening and into early Friday, Aug. 27. Heavy rain fell along the Iowa-Minnesota border with 80 stations measuring at least 1.00 inch; more than 30 stations reported 2.00 inches or greater with 6.50 inches observed near Ringsted (Emmet County). The statewide average rainfall was 0.74 inch. Unstable conditions in northeastern Iowa fired supercell thunderstorms that produced two weak tornadoes near Clear Lake (Cerro Gordo) and Marble Rock (Floyd County) during the early evening hours; crop damage was again reported along with spotty structural damage. Localized flash flooding also occurred as sluggish thunderstorms moved through northeastern Iowa.
Storms continued to pop up over Highway 20 corridor into Saturday morning. The heaviest rain totals ranged from 2.00 inches at Spencer Municipal Airport (Clay County) to 8.74 inches in Elma (Howard County) with widespread totals above 1.50 inches near Waterloo (Linn County) to Mason City (Cerro Gordo County) and northeast; Iowa’s southwestern half experienced dry conditions. Gusty southerly winds and mostly sunny skies pushed afternoon highs into the upper 80s and low 90s. Additional thunderstorms, some severe, pushed into northwestern Iowa ahead of a cold front during the late evening hours. Much of northern Iowa received additional rainfall with higher totals in the northwest corner; Rock Valley (Sioux County) reported 1.01 inches while Sibley (Osceola County) measured 2.76 inches. Totals were generally above 0.50 inch from Mason City west. The front continued south into Sunday, Aug. 29, with morning temperatures in the mid-60s northwest to low 70s southeast.
Weekly precipitation totals ranged from 0.07 inch at Burlington Municipal Airport (Des Moines County) to 13.98 inches at Elma. The statewide weekly average precipitation was 2.26 inch while the normal is 0.97 inch. Multiple south-central stations observed the week’s high temperature of 98 degrees on Aug. 24, on average 15 degrees warmer than normal. Elkader (Clayton County) and Stanley (Buchanan County) reported the week’s low temperature of 50 degrees on Aug. 16, on average six degrees cooler than normal.
