Rain throughout the week resulted in 2.5 days suitable for field work during the week ending May 24, according to the USDA, National Agricultural Statistics Service. Below normal temperatures have slowed crop growth.
Topsoil moisture levels across Iowa rated 2 percent short, 76 percent adequate and 22 percent surplus. West central Iowa is dryer than average, with ratings at 4 percent short, 83 percent adequate and 13 percent surplus.
Subsoil moisture statewide levels rated 1 percent very short, 3 percent short, 79 percent adequate and 17 percent surplus. Ratings in west central Iowa are 2 percent very short, 10 percent short, 83 percent adequate and 5 percent surplus.
Iowa farmers have planted 97 percent of the expected corn crop, three weeks ahead of last year and almost two weeks ahead of the 5-year average. Corn emergence was at 82 percent, an improvement of 20 percentage points from the previous week. The first corn condition rating of the season was 2 percent poor, 17 percent fair, 67 percent good and 14 percent excellent.
The soybean crop moved to 92 percent planted, nearly a month ahead of last year and more than two weeks ahead of average. Farmers in southwest Iowa have more than 25 percent of their soybeans left to plant. Fifty-two percent of the soybean crop has emerged, doubling the amount of soybeans emerged from the previous week.
Hay condition rated 73 percent good to excellent. Pasture condition improved to 66 percent good to excellent. There was little stress on livestock although feedlots remain muddy.
Preliminary weather summary provided by Justin Glisan, Ph.D., state climatologist, Iowa Department of Agriculture and Land Stewardship – Under a stagnant atmospheric pattern across the Midwest, Iowa experienced cool and cloudy conditions through much of the reporting period. The persistent cloud cover and sluggish large-scale flow did not allow temperatures to fluctuate significantly between the daytime and nighttime over several days. Temperatures were up to four degrees cooler than normal with the statewide average temperature of 60.7 degrees, 2.6 degrees below normal. Measurable rainfall was also reported statewide, though less than average totals were observed at a majority of stations.
A cut-off low pressure system continued to spin over northwest Iowa through most of Sunday, May 17. The low moved very slowly as it lacked the large-scale steering flow to move it out of the region. A lingering band of showers left measurable rain totals across northern and eastern Iowa. Kanawha (Hancock County) reported 1.13 inches while Le Claire Lock and Dam (Scott County) reported 1.17 inches. Totals tailed off to a few tenths of an inch in east central Iowa. Cloudy and damp conditions held daytime highs in the mid 50s to low 60s west to east. Overnight lows into Monday did not drop appreciably, remaining in the low 50s under northly winds and a thick stratus cloud deck. Temperatures through the afternoon topped out in the mid to upper 50s with the statewide average high of 58 degrees, 14 degrees cooler than normal.
Similar conditions were reported on Tuesday, May 19, though daytime temperatures did reach into the low 60s across much of Iowa. Light easterly winds were reported overnight into Wednesday with morning temperatures in the low to mid 50s statewide, seasonal for this time of year. Foggy conditions were also reported across southern and western Iowa. As the cloudy day wore on, temperatures remained in the 60s with lower 70s observed in northeastern Iowa.
Winds began to shift to a southeasterly direction into the late night hours with lows in the mid to upper 50s reported across the state. Daytime highs on Thursday, May 21, rose into the low to mid 60s with some peeks of sunshine in western Iowa. A weak disturbance pushed into Iowa bringing light rain to some western stations, though generally less than 0.01 inch.
Overnight temperatures into Friday remained in the mid to upper 50s with low-lying fog under continuing cloudiness. Southeasterly winds helped push daytime temperatures into the upper 60s and low 70s ahead of slow-spinning low pressure system along the Kansas-Nebraska border.
The system pushed into Iowa during the late night hours, bringing showers and thunderstorms through Saturday, May 23. Some thunderstorms turned severe across eastern Iowa shortly after noon. A few weak tornadoes were reported, including one with an EF-1 rating in Morse (Johnson County), which caused some minor structural damage on a farm.
A secondary line of strong thunderstorms pushed into western Iowa overnight into Sunday morning, bringing locally heavy rain. Two-day totals reported at 7 am were generally at or above 0.20 inch across much of the state with the highest amounts reported in northwest Iowa; Sioux Rapids (Buena Vista County) reported 1.81 inches with the statewide average of 0.51 inch.
Weekly rain totals ranged from 0.03 inch in Keosauqua (Lee County) to 2.14 inches in Maquoketa (Jackson County). The statewide weekly average precipitation was 0.79 inch while the normal is 1.05 inches. Keokuk Lock and Dam (Lee County) reported the week’s high temperature of 88 degrees on May 24, 12 degrees warmer than normal. Sibley (Osceola County) reported the week’s low temperature of 45 degrees on the May 18, one degree cooler than normal.
