Provided by Justin Glisan, Ph.D., State Climatologist, Iowa Department of Agriculture and Land Stewardship
The stretch of unseasonably cold reporting periods continued through the first week of May with temperature departures ranging from four to eight degrees below normal across Iowa; the statewide average temperature was 51.3 degrees, 5.2 degrees below normal. Rain fell at all reporting stations with pockets of slightly above average totals in west-central and eastern Iowa, though the remainder of the state experienced below average totals of near an inch along the Iowa-Minnesota border.
Overcast skies continued through Sunday (1st) afternoon with a northwesterly wind shift into the evening hours. Daytime temperatures held in the upper 40s north to low 50s south with slightly warmer conditions in the southwest corner where skies were clearing. Light rain began pushing into southwestern Iowa just after 7:00 am on Monday (2nd) in advance of a large area of low pressure. Sunny skies were observed in eastern Iowa allowing afternoon highs to push into the upper 50s as thick clouds and rainfall held temperatures in the 40s over the rest of the state. The disturbance, along with pockets of moderate rainfall, continued to propagate through Iowa overnight into Tuesday (3rd) as the backside of the low held light showers in eastern Iowa. Overcast conditions persisted even as the low moved out of the region, accompanied by light northeasterly winds and highs in the 50s. Event rain totals varied from 0.50 to 0.75 inch across a broad swath of the state with only the northwest corner missing out; the statewide average rainfall was 0.65 inch with 25 stations measuring at least an inch. Breaks in the clouds began to form over northern Iowa during the late night hours with patchy fog reported just before sunrise of Wednesday (4th). Clear skies did not last long in western Iowa but held on in the east where upper 50s and low 60s were reported. An upper level disturbance brought light showers into western Iowa overnight into Thursday (5th) morning with totals generally between 0.10 and 0.25 inch, though heavier pockets were observed in the northwest; Remsen (Plymouth County) measured 0.40 inch.
Spotty showers remained across parts of southern and eastern Iowa with easterly winds and temperatures in the mid to upper 50s. Rain showers finally dissipated along the Iowa-Missouri border very early on Friday (6th) as skies cleared through the afternoon. Warmer conditions were present over the state’s western half with mid to upper 60s observed while eastern Iowa held in the low 60s. Saturday (7th) was the most pleasant day of the week with southerly winds, brilliant sunny skies and near-seasonal temperatures in the 70s; the statewide average high was 71 degrees, three degrees above normal. Clouds increased into the nighttime hours as another disturbance brought showers and thunderstorms into Iowa’s western half early Sunday (8th) morning. Totals reported at 7:00 am showed moderate rainfall in west-central to northwest Iowa and lesser amounts farther east; Sac City (Sac County) measured 0.63 inch while general totals were a few tenths of an inch at a majority of stations receiving rain.
Weekly precipitation totals ranged from 0.05 inch at Knoxville (Marion County) to 1.75 inches at Sac City. The statewide weekly average precipitation was 0.91 inch while the normal is 0.96 inch. Spencer Municipal Airport (Clay County) reported the week’s high temperature of 77 degrees on the 7th, 10 degrees above normal. Several northern stations reported the week’s low temperature of 29 degrees on the 4th, on average 13 degrees below normal. Four-inch soil temperatures were in the low 50s east to upper 50s west as of Sunday.