The southern third of Iowa finally received some much-needed rain, which reduced the days suitable for fieldwork to 5.1 during the week ending July 2, 2023, according to the USDA, National Agricultural Statistics Service. Field activities included cutting hay and spraying crops. Some reports were received of farmers getting equipment ready to start the oat harvest soon.
Topsoil moisture condition across Iowa rated 17 percent very short, 38 percent short, 44 percent adequate and 1 percent surplus. Ratings in west central Iowa also improved slightly, to 29 percent very short, 38 percent short, 30 percent adequate and 3 percent surplus.
Subsoil moisture condition statewide rated 21 percent very short, 40 percent short, 38 percent adequate and 1 percent surplus. Ratings in west central Iowa were 33 percent very short, 34 percent short, 31 percent adequate and 2 percent surplus.
Reports of corn starting to silk were received, hitting 4 percent this week. Corn condition rating improved to 61 percent good to excellent. Twenty-five percent of soybeans were blooming, five days ahead of last year and two days ahead of the 5-year average. There were reports of soybeans starting to set pods. Soybean condition rose to 53 percent good to excellent.
The state’s second cutting of alfalfa hay reached 35 percent complete, eight days ahead of last year and six days ahead of the average. Hay condition improved slightly to 33 percent good to excellent. Pasture condition rated 24 percent good to excellent. Livestock producers continued to supplement with hay as pasture conditions remained comparable to the previous week.
Weather summary provided by Justin Glisan, Ph.D., state climatologist, Iowa Department of Agriculture and Land Stewardship – A large-scale atmospheric circulation shift brought several rounds of strong to severe thunderstorms over southern Iowa late in the reporting period. This configuration, called a “Ring of Fire,” allowed waves of storms to propagate along the northern boundary of a thermal ridge situated south of Iowa. The southern one-third of the state reported above-average rainfall with drier conditions north. Weekly temperatures were near-seasonal with a statewide average of 72.5 degrees, 0.5 degree cooler than normal.
Scattered showers spun across eastern Iowa on the backside of a departing low-pressure center through Sunday afternoon, June 25. Gusty northwesterly winds also developed as daytime temperatures held in the 70s. Rainfall totals were generally in the 0.10 to 0.20 inch-range with several northeastern stations reporting higher totals; gauges in Dundee (Delaware County) and near Decorah (Winneshiek County) measured 0.42- and 0.45-inch amounts, respectively. Overnight conditions remained mostly cloudy over northern Iowa as temperatures dropped into the 60s.
Clouds lingered over most of the state on Monday though sunny skies in southwestern Iowa pushed high temperatures into the mid-80s at several stations. Light, variable winds developed on Tuesday morning, June 27, with lows in the 50s and patchy fog at many reporting sites. Thick Canadian wildfire smoke moved into eastern Iowa later in the day, creating low visibility and degraded air quality. High temperatures were generally in the low to mid 80s with slightly cooler conditions northwest.
Scattered showers developed through the evening hours in western Iowa as a second wave formed after midnight on Wednesday. A wider shield of rain spread from north central into eastern Iowa after sunset before dissipating. Additional thundershowers popped up in southern Iowa over the late afternoon hours as smoky skies helped to hold temperatures in the lower 80s while northwestern stations registered upper 80s under clear skies. Totals were generally less than 0.20 inch with isolated swaths near 0.50 inch in central Iowa.
Thursday, June 29, was active as morning severe storms in southwest Iowa consolidated into a squall line through southeastern Iowa. Severe straight-line winds were widespread with pockets of mature tree damage and flattened crops from Bedford (Taylor County) to Fort Madison (Lee County). The line was later determined to meet the threshold of a derecho, given the path length and width as it moved through Illinois and Indiana.
Another wave of thunderstorms formed along the same line on Friday morning, though with less intense activity and rainfall spreading farther north. Forty stations received more than an inch of rain from the two events, 15 of which measured more than 2.00 inches; Adair (Adair County) observed 2.00 inches while 3.26 inches fell at Lamoni Municipal Airport (Decatur County). Most stations across the southern three tiers of counties received at least 0.50 inch as totals approached 0.20-0.30 inch through central Iowa with a statewide average of 0.60 inch. Afternoon conditions returned to calm over Iowa with partly sunny skies and temperatures in the upper 70s and low 80s.
Rain showers formed overnight into Saturday, July 1, north of low-pressure center pushing across Missouri. More thundershowers spread into northeastern Iowa and refired across the southwest though the day with moderate rainfall in south-central and southeastern Iowa. Another 16 stations measured at least an inch with more than half of the locations hitting at least 0.40 inch; Donnellson (Lee County) poured out 3.43 inches. Sunday morning lows ranged from the upper 50s and low 60s in western Iowa to high 60s in eastern Iowa, where showers lingered.
Weekly rain totals ranged from no accumulation at several northwest stations to 6.20 inches at Donnellson. The statewide weekly average precipitation was 1.15 inches, while the normal is 1.10 inches. Osceola (Clarke County) reported the week’s high temperature of 94 degrees on June 29, nine degrees warmer than normal. Battle Creek (Ida County) and Guthrie Center (Guthrie County) reported the week’s low temperature of 50 degrees on June 27, on average 11 degrees cooler than normal.
