Rain across most of Iowa improved dry soil conditions during the week ending Aug. 25, according to the USDA, National Agricultural Statistics Service. Statewide there were 5.0 days suitable for fieldwork. Reporters throughout the state mentioned the need for warmer weather as cooler than normal temperatures have slowed crop development. Fieldwork activities included spraying fungicides and insecticides on late planted crops and harvesting hay. Topsoil moisture condition across the state was rated 3 percent very short, 20 percent short, 75 percent adequate and 2 percent surplus. Topsoil moisture in west central Iowa rated 5 percent very short, 9 percent short, 80 percent adequate and 6 percent surplus. The Northwest District was the only district where topsoil moisture condition became drier this past week.
Subsoil moisture condition statewide was rated 4 percent very short, 20 percent short, 74 percent adequate and 2 percent surplus. Levels in west central Iowa were 7 percent very short, 10 percent short, 79 percent adequate and 4 percent surplus.
Seventy-six percent of the corn crop has reached the dough stage, 11 days behind last year and nine days behind the 5-year average. Twenty-one percent of the crop reached the dented stage, two weeks behind last year and nine days behind average. Corn condition rated 65 percent good to excellent.
Nearly all the soybean crop has started to bloom at 96 percent statewide, 11 days behind average. Eighty-four percent of the crop has started setting pods, 17 days behind last year and 12 days behind average. Soybean condition rated 62 percent good to excellent.
The third cutting of alfalfa hay reached 49 percent, 11 days behind average.
Hay condition rated 57 percent good to excellent. Pasture condition improved slightly for the first time in seven weeks and rated 44 percent good to excellent. There were no reported livestock issues this past week.
Weather summary provided by Justin Glisan, Ph.D., state climatologist, Iowa Department of Agriculture and Land Stewardship – Continued wetter-than-average conditions were found across central and southern Iowa during the reporting period. Locations in northeastern Iowa experienced rainfall deficits up to and slightly over an inch. Unseasonable coolness also persisted with temperatures up to five degrees below average across parts of Iowa. The statewide average temperature was 68.5 degrees, 3.1 degrees below normal.
A low pressure system moved out of Iowa through the afternoon hours on Sunday, Aug. 18, leaving measurable rainfall across the southern half of the state. Northwest winds and partly cloudy conditions kept high temperatures in the low to mid 70s in northern Iowa and low 80s in the south.
Rain totals reported at 7 a.m. on Monday were heaviest in southeast Iowa with a station in Ottumwa (Wapello County) observing 0.92 inches. Widespread totals between 0.10 inch and 0.25 inch were also reported. Conditions during the day were warm and humid with highs in the mid-80s and variable winds. Daytime conditions created an unstable atmosphere primed for overnight convection; discrete thunderstorms began to fire just before midnight in north-central Iowa. These thunderstorms quickly turned severe and coalesced into strong mesoscale convective system (MCS) that moved southeast through central Iowa into the morning hours of Tuesday, Aug. 20.
Along with multiple severe straight-line wind events, three tornadoes were reported. Two tornadoes, one hitting Tracy (Marion County) and the other moving through Badger Creek State Park (Madison County), were rated EF-1 with peak winds estimated at 110 mph. A strong EF-3 rated tornado, with estimated winds of 150 mph, caused substantial damage to several structures in Lacona (Warren County).
In terms of rainfall, over 100 stations reported an inch or more. In locations with stronger storms, rain totals varied from 2.00 inches Eldora (Hardin County) to 4.30 inches in Coon Rapids (Carroll County). The statewide average rainfall was 0.75 inch.
Another low pressure system moved through Iowa on Wednesday bringing additional widespread rain to much of the state. Totals were highest across central and southern Iowa. Pella (Marion County) reported 2.22 inches while Rathbun Dam (Appanoose County) reported 2.10 inches.
Iowa experienced near perfect weather conditions Thursday and Friday, Aug. 22-23, as a large dome of high pressure dominated the upper Midwest, bringing clear and comfortable conditions. Daytime highs were in the mid to upper 70s with unseasonably cool overnight lows in the mid to upper 50s, on average five degrees below normal.
Pleasant and dry conditions continued through the weekend with partly cloudy skies and a light southeasterly wind on Saturday. Temperatures remained in the mid-70s with low relative humidity. Overnight lows into Sunday dipped into the upper 50s to low 60s as cloud cover began to increase across the state.
Weekly rainfall totals ranged from no accumulation in Decorah (Winneshiek County) to 4.47 inches in Guthrie Center (Guthrie County). The statewide weekly average precipitation was 1.12 inches, slightly above the normal of 0.98 inch.
The week’s high temperature of 92 degrees was reported Aug. 20 in Little Sioux (Harrison County) and Oakland (Pottawattamie County), on average nine degrees above normal. Cresco (Howard County) reported the week’s low temperature of 47 degrees on Aug. 22, nine degrees below average.
