A large swath of Iowa received rainfall this week reducing the days suitable for fieldwork to 5.3 during the week ending Sept. 24, 2023, according to the USDA, National Agricultural Statistics Service. Field activities for the week were mainly harvesting corn and soybeans.
Topsoil moisture condition across Iowa rated 27 percent very short, 46 percent short, 26 percent adequate and 1 percent surplus. Ratings in west central Iowa were 21 percent very short, 48 percent short, 28 percent adequate and 3 percent surplus.
Subsoil moisture condition statewide rated 35 percent very short, 44 percent short, 20 percent adequate and 1 percent surplus. Ratings in west central Iowa were 36 percent very short, 42 percent short, 20 percent adequate and 2 percent surplus.
Corn maturity reached 83 percent this week, nilne days ahead of last year and 12 days ahead of the 5-year average. Corn harvested for grain reached 9 percent statewide, six days ahead of last year and four days ahead of the average. Moisture content of field corn being harvested for grain was at 21 percent. Corn condition improved slightly to 50 percent good to excellent.
Soybeans coloring or beyond reached 95 percent, roughly one week ahead of both last year and the average. Soybeans dropping leaves was 75 percent this week, six days ahead of last year and five days ahead of normal. Soybeans harvested reached 11 percent, three days ahead of last year and one day ahead of normal. Soybean condition remained steady at 47 percent good to excellent.
Pasture condition rated 17 percent good to excellent. Livestock conditions have not changed much from last week, with concerns of hay being in short supply for next year.
Weather summary provided by Justin Glisan, Ph.D., state climatologist, Iowa Department of Agriculture and Land Stewardship – In a much-welcome shift, Iowa stations reported beneficial rainfall over the reporting period with swaths of 2-to-3-inch above normal totals from southwest to northeast; southeast stations reported deficits more than 0.50 inch. Temperatures were also unseasonably warm statewide with the weekly average coming in at 66.4 degrees, 7.2 degrees warmer than normal.
The daylight hours of Sunday, Sept. 17, were pleasant with light winds as highs held in the low to mid 70s under partly cloudy skies. Clearing allowed overnight lows on Monday to dip into the low to mid 40s at many Iowa stations, though low 50s were observed at some locations in the south. Gusty southerly winds built in through the day with temperatures in the upper 70s and low 80s.
Showers and thunderstorms began to form across northwestern Iowa as a stationary front shifted into the state after sunset. A more widespread shield of rain formed in central to eastern Iowa as more concentrated storms continued in west central Iowa into Tuesday, Sept. 19. Stagnant thunderstorms with vivid lightning continued to redevelop over a broad swath of central Iowa into the evening hours with lighter showers farther east. High temperatures stayed in the low 60s where rain was present while upper 60s to mid-70s were found over northern Iowa. Additional slow-moving storms developed along the Iowa-Nebraska border into Wednesday morning before falling apart a few hours before sunrise.
More than 50 stations reported at least an inch of rain through the event with the highest totals on either side of I-35; Jefferson (Greene County) measured 2.04 inches while 3.40 inches was reported in Bondurant (Polk County). Stations around the periphery reported widespread totals in the 0.30- to 0.50-inch range with a statewide average of 0.43 inch. Isolated showers formed behind the disturbance in the southwest and over a wider swath of eastern Iowa. Afternoon temperatures remained in the upper 70s and low 80s. Rain amounts were generally below 0.20 inch though stations in Fayette (Fayette County) and Atlantic (Cass County) collected 0.50 and 0.65 inch, respectively.
Winds shifted to the east overnight as fog formed at many stations into Thursday morning, Sept. 21. Temperatures dropped into the low 50s across central and northern Iowa. Daytime conditions were partly to mostly cloudy over Iowa’s eastern two-thirds as another complex of thunderstorms moved along the Iowa-South Dakota border later in the day; Sioux City Airport (Woodbury County) collected 1.92 inches.
Rain showers pushed through southern Iowa into Friday morning with a more organized line of thunderstorms draped across northern Iowa. Stronger storms fired across northeastern Iowa into the evening hours, spinning up a weak tornado near Blairstown (Benton County). Heavy rain fell over the Exceptional Drought (D4) region, causing isolated flash flooding and beneficial rain totals; Decorah (Winneshiek County) reported 3.44 inches while two stations in Chickasaw County observed 3.80 and 5.08 inches, respectively. A handful of stations in north central Iowa also collected more than 200 percent of normal weekly rainfall.
A strong cold front pushed through Iowa on Saturday, Sept. 23, producing multiple severe-warned storms and a strong bowing line across northern Iowa over the late afternoon and early evening hours. An additional narrow line moved into southern Iowa through midnight, though it did not have ample energy to stay together. Rain totals reported at 7 am on Sunday showed a wide swath of Iowa’s northwestern half receiving at least 0.50 inch with the highest totals from 1.01 inches in Rockwell City (Calhoun County) to 1.72 inches in Webster City (Hamilton County).
Weekly precipitation totals ranged from 0.02 inch in Burlington (Des Moines County) to 5.40 inches in Ionia (Chickasaw County). The statewide weekly average precipitation was 1.09 inches while the normal is 0.86 inch. Lamoni (Decatur County) reported the week’s high temperature of 89 degrees on Sept.19, 12 degrees warmer than normal. Elkader (Clinton County) reported the week’s low temperature of 37 degrees on the Sept. 19, 10 degrees cooler than normal.
