Some much-needed rainfall across western Iowa resulted in 5.6 days suitable for fieldwork during the week ending Aug. 6, 2023, according to the USDA, National Agricultural Statistics Service. Field activities included cutting and baling hay as well as applying pesticides and fungicides. Increased precipitation helped alleviate some crop stress although conditions remain dry.
Topsoil moisture condition across Iowa rated 18 percent very short, 41 percent short, 40 percent adequate and 1 percent surplus. In west central Iowa topsoil moisture condition rated 24 percent very short, 36 percent short, 39 percent adequate and 1 percent surplus. Those ratings are much improved since last week.
Subsoil moisture condition statewide rated 19 percent very short, 47 percent short, 33 percent adequate and 1 percent surplus. Ratings in west central Iowa were 29 percent very short, 38 percent short, 32 percent adequate and 1 percent surplus.
Corn silking hit 97 percent this week. Fifty-eight percent of the corn crop has reached the dough stage or beyond, three days ahead of both last year and the 5-year average. Sixteen percent of the corn crop has reached the dent stage, nine days ahead of last year and 1 week ahead of normal. Corn condition remained steady at 59 percent good to excellent.
Ninety-six percent of soybeans were blooming. Soybeans setting pods reached 75 percent, five days ahead of last year and three days ahead of the 5-year average. Soybean condition fell 2 percentage points to 53 percent good to excellent. Oats harvested for grain reached 80 percent.\
The state’s second cutting of alfalfa hay reached 97 percent complete, one week ahead of last year and eight days ahead of the average. The state’s third cutting of alfalfa hay reached 51 percent complete, two weeks ahead of last year and 12 days ahead of the 5-year average. Hay condition rated 36 percent good to excellent. Pasture condition rated just 22 percent good to excellent. Livestock producers continued to supplement with hay due to the prolonged dry conditions.
Weather summary provided by Justin Glisan, Ph.D., state climatologist, Iowa Department of Agriculture and Land Stewardship – Several western and southern Iowa stations reported a season’s worth of rainfall over the last week as an unseasonable wet pattern brought several waves of showers and thunderstorms through Iowa. Eastern Iowa stations missed out on much of the rainfall with widespread deficits approaching an inch. Temperatures varied from slightly cooler to near-normal south while up to two degrees warmer than normal over Iowa’s northern two-thirds; the statewide average temperature was 74.0 degrees, 2.0 degrees warmer than normal.
Showers and thunderstorms pushed across extreme western Iowa later Sunday afternoon and evening, July 30, with daytime temperatures in the low to mid 80s. A second wave formed overnight in Iowa’s southwest corner and dissipated later Monday morning. Rain totals were less than 0.20 inch, though eight stations reported more than at least an inch; 1.04 inches was measured at Red Oak (Montgomery County) with Hastings (Mills County) collecting 1.76 inches. Southeasterly winds built in throughout the day with afternoon highs similar to the previous day.
Fog developed in west central Iowa near sunrise on Tuesday, Aug. 1, as morning lows varied from the mid-60s east to low 70s west under partly cloudy skies. Clouds increased across western Iowa after noon as temperatures rose into the low to mid 80s with gustier southeasterly winds. Showers pushed through southern Iowa into the later evening hours as a line of stronger storms again formed in southwestern Iowa, producing locally heavy rainfall and flash flood warnings through late Wednesday morning. Most of Iowa’s southwestern half reported measurable totals with a widespread swath of at least 0.50 inch; 60 stations hit this threshold with nearly 30 measuring at an inch or more. Two Harrison County locations, Little Sioux and Blencoe, registered 4.25 inches and 4.50 inches, respectively.
Overcast skies and fog persisted into Thursday, Aug. 3, with unseasonably warm morning lows from the low 60s north to the low 70s south. Mostly cloudy conditions hung around southern Iowa as peeks of sunshine were visible across northern Iowa with afternoon highs in the 80s under a light easterly wind.
Ample surface moisture and calm winds allowed fog to redevelop into the early hours of Friday with temperatures holding in the mid-60s. Showers developed in southwestern Iowa through the afternoon as a low-pressure center pushed into northern Missouri, slowly moving due east through the remains of the day and into the wee hours of Saturday. Several slow-moving thunderstorms dropped heavy amounts of rain in southeastern Iowa; Augusta (Lee County) recorded 3.95 inches, while Burlington’s (Des Moines County) National Weather Service Station and airport observed 4.44 inches and 6.14 inches, respectively.
Another broad-scale and more powerful low-pressure spinning over North Dakota fired showers and a line of severe thunderstorms over northwestern Iowa during the late afternoon as southeasterly winds pumped southerly moisture into Iowa. The initial line spawned a weak tornado near Sioux Center (Sioux County) along with flash flood warnings over several counties. The line sped southeast as moderate rain showers filled in behind, bringing totals above 0.50 inch to most of Iowa’s western half; the average rainfall was 0.62 inch. Several west central and northwest stations measured nearly a month’s worth of rain with 3.14 inches at Holstein (Ida County) to 4.30 inches in Remsen (Plymouth County). Thunderstorms continued into eastern Iowa at daybreak on Sunday, Aug. 6, with lows in the mid to upper 60s mostly and thick, overcast skies statewide.
Weekly precipitation totals ranged from no accumulation across northeast Iowa to 8.45 inches in Little Sioux, a record 7-day total for the station that has been reporting for 23 years. The statewide weekly average precipitation was 1.49 inches while the normal is 0.96 inch. Lamoni (Decatur County) reported the week’s high temperature of 93 degrees on July 30, six degrees warmer than normal. Oelwein (Fayette County) reported the week’s low temperature of 50 degrees on July 31, 13 degrees cooler than normal.
