Weather SummaryWritten by Theresa Rose on December 3, 2019
Provided by Justin Glisan, Ph.D., State Climatologist, Iowa Department of Agriculture and Land Stewardship
Multiple strong low pressure systems brought active weather to the Midwest, capping off the last week of November. All forms of precipitation — from rain and snow to freezing rain and hail — were reported across Iowa. Much of the state experienced unseasonable wetness with up to an inch above average across northern Iowa. Only southwestern Iowa reported slight deficits. Above average snowfall was also reported across northwestern Iowa with anywhere from two to six inches above normal. In terms of temperature, Iowa’s statewide average was 4.5 degrees warmer than normal at 34.2 degrees.
Warmer than average conditions prevailed across Iowa through Sunday (24th) under partly to mostly sunny skies. Daytime highs reached into the upper 40s across northern Iowa while southern Iowa reported mid to upper 50s. The average statewide high was 53 degrees, 12 degrees above normal. Slightly cooler temperatures persisted into Monday (25th) as a weak cold front pushed through, shifting winds out of the northwest into the evening hours. Light rain associated with the frontal passage was reported at a handful of stations. Overnight lows remained well above average with departures up to 16 degrees warmer than average; the average morning low of 30 degrees was eight degrees above normal.
Cloud cover began increasing on Tuesday (26th) as winds shifted to the northeast ahead of the first low pressure to impact Iowa. A mix of rain and snow fell across central and southern Iowa and transitioned to moderate snow across northwestern Iowa during the nighttime and overnight hours. Near blizzard conditions were reported as strong northern winds built in behind the system. Sustained winds peaked above 30 mph with gusts in the 35-40 mph range; Estherville Municipal Airport (Emmet County) reported a peak wind gust of 47 mph with near whiteout conditions. Snow totals reported on Wednesday (27th) morning were highest in northwest and north-central Iowa with Sanborn (O’Brien County) observing 8.6 inches; over 40 stations reported totals above three inches.
Thanksgiving Day (28th) was overcast with light rain and snow showers. Liquid equivalent totals were generally under 0.30 inch while high temperatures remained in the upper 20s and low 30s. An additional wave of moderate rain moved through Iowa on Friday (29th) as temperatures remained above freezing. Heavier showers and isolated freezing rain were observed in Iowa’s northwest corner with stations in O’Brien, Plymouth and Sioux counties reporting totals over an inch.
Precipitation cleared the state during Saturday (30th) morning, though overcast skies remained across much of Iowa in advances of a third low pressure system moving through Nebraska. Highs ranged from the upper 40s north to low 50s south, where partly sunny skies allowed for warmer temperatures. Unstable atmospheric conditions during the late afternoon allowed isolated strong thunderstorms to form across central Iowa. A brief spin-up rope tornado was reported near Guthrie Center (Guthrie County), though no damage was observed. Pea-sized hail was also reported around the Des Moines (Polk County) metro area. As the last hours of November ticked away, the low pushed into Iowa, bringing light rain and snow showers across western Iowa as overnight lows hovered around the freezing mark; the average statewide low was 31 degrees, 12 degrees above normal. As of 7 a.m. on Sunday (1st) snow totals were light and generally under a half of an inch.
Weekly precipitation totals ranged from 0.15 inch in Red Oak (Montgomery County) to 2.27 inches in Sibley (Osceola County). The statewide weekly average precipitation was 0.83 inch, while the normal is 0.48 inch. The average snowfall across Iowa was 1.50 inches with Sibley (Osceola County) reporting 10.4 inches.
The week’s high temperature of 61 degrees was observed on the 24th at Knoxville (Marion County) and Oskaloosa (Mahaska County), on average 18 degrees above normal. The week’s low temperature of 18 degrees was reported on the 28th at Mason City Municipal Airport (Cerro Gordo County), which is the climatological normal. Soil temperatures as of Sunday were generally in the mid to upper 30s.