Weather Report for Iowa, September 9, 2018
The first full week of September had above average precipitation statewide. Temperatures were near to slightly above average, especially in eastern Iowa. Multiple waves of showers and thunderstorms moved across Iowa Monday through Wednesday, bringing locally heavy rain and isolated severe weather.
On Labor Day, most of Iowa’s southeastern two-thirds reported rainfall. During the evening hours, two counties in eastern Iowa had tornadic activity; in Linn County, two EF-1 tornadoes with winds between 100 and 110 mph were reported near Cedar Rapids. Minor structural damage, uprooted trees, and blown over crops were observed. Vinton (Benton County) also reported two EF-0 tornadoes with winds in excess of 80 mph.
On Tuesday many parts of northwestern Iowa that missed out on Monday’s rain received above normal accumulations. Some thunderstorms were severe, with Algona (Kossuth County) reporting 4.02 inches of rain (3.92 inches above average) and structural damage from a brief tornado touchdown. A cold front moved through on Wednesday bringing widespread measurable rainfall into Thursday. Flash flood warnings were issued as slow-moving storms lingered over central and eastern Iowa. Two-day rainfall totals averaged above one inch across 75 counties; Montezuma (Poweshiek County) reported 5.20 inches.
Thursday was cooler than average statewide with highs in the low to mid-70s. The southeastern quadrant observed measurable rainfall; Ottumwa (Wapello County) reported 0.42 inches. Rain showers moved into Iowa’s southern third early Friday and lingered into Saturday as the remains of Tropical Depression Gordon moved through Missouri. Rainfall totals were generally under an inch with Bloomfield (Davis County) reporting 1.10 inches.
The rest of the weekend saw pleasant conditions across Iowa. Temperatures were unseasonably cool with highs ranging from the mid-60s to mid-70s. Sunday was the nicest day of the week, with generally sunny skies and dry conditions.
By Dr. Justin Glisan, State Climatologist, Iowa Department of Agriculture and Land Stewardship