(Des Moines)--An unsettled and active weather pattern across the Midwest brought multiple days of showers and thunderstorms across Iowa during the reporting period. The western two-thirds of Iowa experienced above average rainfall while the northeast corner was slightly drier than average. Unseasonable coolness also continued across the state. Temperatures averaged 67.2 degrees, 4.1 degrees below normal.
A warm front draped across central Iowa during mid-afternoon Sunday (16th) set up a stark temperature contrast across the state. Eastern Iowa reported highs in the mid to upper 60s, around 10-15 degrees below average. Temperatures across western Iowa reached the low to mid 80s, near normal for June. A cold front moved through on Monday (17th) bringing measurable rainfall across Iowa’s northwestern third. Slow-moving thunderstorms brought locally heavy amounts; rain totals ranged from 0.25 inch to over 1.50 inches; Pocahontas (Pocahontas County) reported 1.60 inches, 1.43 inches above average. The cold front continued to move through Iowa on Tuesday (18th) with measurable rain across much of the state. Isolated thunderstorms fired in Iowa’s southwestern corner; Atlantic (Cass County) and Randolph (Fremont County) reported 24-hour totals of 1.58 and 1.84 inches, respectively. High temperatures ranged from the upper 70s to low 80s in southern Iowa and 70s across the rest of the state. The average statewide high was 74 degrees, eight degrees below normal.
A weak low pressure system moving through northern Missouri brought showers to southern Iowa early on Wednesday (19th). Additional development over central and southeastern Iowa during the afternoon and evening hours brought locally heavy rainfall to a handful of stations across three counties in extreme southeast Iowa; Salem (Henry County) reported 2.74 inches while Keokuk Lock and Dam (Lee County) observed 1.77 inches. A stagnant low pressure system sat over the Midwest beginning Thursday (20th), bringing waves of showers and thunderstorms through the weekend. Isolated showers and a few thunderstorms moved through Iowa during Thursday morning and afternoon. Western Iowa reported the highest totals with Sac City (Sac County) observing 2.40 inches, 2.21 inches above average. High temperatures remained cooler than average under cloudy skies, generally in the 70s statewide.
Friday (21st) started off very wet as a line of strong thunderstorms sped across the state, leaving measurable rainfall at most stations. A second round of storms moved through southern Iowa in the late night hours into Saturday (22nd). Rain totals at 7:00 am were highest in central Iowa with Des Moines International Airport (Polk County) reporting 2.41 inches. Locations east and west had general totals between 0.20 to 1.00 inch; 20 stations reported over an inch with the statewide average at 0.45 inch, 0.28 inch above average. The remainder of Saturday was cool and wet across much of Iowa with highs in the mid to upper 70s, six degrees below normal. Thunderstorms moved into southwestern Iowa during the late afternoon and moved into central and eastern Iowa during the late evening hours. Some locations experienced torrential downpours and flash flooding in central Iowa from the large convective complex. There were also a few reports of severe hail and high winds. The system slowly moved through Iowa into Sunday (23rd) morning. Rain totals ranged from 0.01 inch in Sac City (Sac County) to 1.98 inches in Des Moines (Polk County).
Weekly rainfall totals ranged from 0.23 inch at Cresco (Howard County) to 5.01 inches in Allerton (Wayne County). The statewide weekly average precipitation was 1.73 inches, while the normal is 1.17 inches. The week’s high temperature of 86 degrees was observed in Oakland (Pottawattamie County) on the 17th, four degrees above normal. Cedar Rapids (Linn County) reported the week’s low temperature of 49 degrees on the 18th, 12 degrees below average.