Monthly Weather Report

IOWA MONTHLY WEATHER SUMMARY – APRIL 2022

General Summary

Temperatures averaged 43.8 degrees or 4.9 degrees below normal while precipitation totaled 3.12 inches or 0.55 inch below normal. April 2022 ranks as the 12th coldest and 67th wettest/83rd driest April in 150 years of statewide records. A colder April last occurred in 2018, which was also the coldest on record. A wetter April last occurred in 2017 while 2021 was drier.

Temperatures

Iowa experienced many cold and windy days in April, which is climatologically the windiest month for the state. On average, statewide temperatures were three to six degrees below normal with all National Weather Service (NWS) co-op stations observing negative departures.

April’s statewide average maximum temperature was 60.1 degrees, 5.3 degrees below normal while the average minimum temperature was 32.8 degrees, 4.4 degrees below normal. Little Sioux (Harrison County) reported the month’s high temperature of 90 degrees on the 12th, 29 degrees above average. Algona (Kossuth County) reported the month’s low temperature of 11 degrees on the 1st, 18 degrees below normal.

Heating Degree Days

Home heating requirements, as estimated by heating degree day totals, averaged 37% more than last April and 30% more than normal. Heating degree day totals are running 1% less than last year at this time and 2% less than normal.

Precipitation

Portions of central to north-central as well as eastern Iowa reported totals approaching two inches above normal. Western Iowa was the driest part of the state with precipitation deficits on the order of one to two inches.

Weather highlights in April include a fast-moving disturbance that brought widespread rainfall to much of Iowa through April 2nd. Most of Iowa’s stations observed measurable precipitation, both liquid and frozen, with several locations picking up a few inches of snow; Dubuque Regional Airport measured 4.5”. Liquid-equivalent totals were in the range of 0.25” to 0.75” with Bellevue Lock and Dam (Jackson County) reporting 0.83”. A slow-moving low pressure system formed on the 5th and moved through the Dakotas into Minnesota where it became cut off from the steering flow and remained nearly stationary. Widespread showers formed over Iowa as most stations observed at least a tenth of an inch. Iowa’s eastern quarter measured totals from 0.25” to near 1.00” in the southeastern counties with Burlington 6.5 SSW (Des Moines County) registering 1.12”.

On the 12th, southeasterly winds in the 20 to 30 mph range pumped in warm, moist air ahead of a strong cold front; a warm front moving north across southeastern Iowa pushed temperatures into the 80s within the warm sector of the strong low pressure system. The mix of unseasonably warm air, atmospheric instability and wind shear over northern Iowa fired supercell thunderstorms late in the afternoon. Several of these storms produced tornadoes with a strong EF-2 that moved through Gilmore City (Humboldt County), producing damage to multiple farms. As the cold front swept across Iowa during the late afternoon and evening hours, a second round of severe weather impacted western Iowa with many reports of large hail and strong straight-line winds. The line lost energy overnight as it pushed east, though moderate rain was observed. Rain totals reported at 7:00 am on the 13th were highest in north-central Iowa with nine stations measuring over an inch; much Iowa’s western half reported totals between 0.25 to 0.75”.

Easter Sunday saw light rain and snow showers continue through the afternoon with a band of 1.5 – 3.0” snow totals measured from south-central into northwestern Iowa; Indianola 0.8 SSW (Warren County) reported 4.0”. Most of Iowa’s stations observed measurable precipitation totals on the morning of the 18th in the range of 0.20 to 0.40”. The later part of April was more active with a line of showers forming in the late evening of the 21st over southern Iowa and pushed north along an atmospheric boundary. The area of rain expanded across central and northern Iowa as severe storms pushed into western Iowa prior to sunrise on the 22nd. Pockets of heavier rainfall associated with slow-moving thunderstorms produced flash flooding across several central Iowa counties with rain rates approaching 3.00” per hour. Almost 50 stations reported at least an inch of rain with Maxwell (Story County) measuring 3.20” and a statewide average coming in at 0.53”. A line of strong thunderstorms rapidly formed ahead of a strong low pressure disturbance and moved across western Iowa after sunrise on the 23rd. Some storms turned severe as the line raced into central Iowa before dissipating northeast. A second, stronger squall line formed along the low’s attendant cold front during the late afternoon hours. Several storms turned severe through the evening hours with multiple reports of 60 - 70 mph winds and quarter-sized hail; a weak tornado was also spotted near Sheldahl (Boone County). Pockets of heavier rain totals were found in south-central Iowa with general storm amounts between a tenth and half of an inch.

An area of light to moderate showers formed in northeastern Iowa around midnight and shifted into eastern Iowa through the afternoon of the 28th. Rain totals from northern to eastern Iowa were generally around a few tenths of an inch; Estherville (Emmett County) reported 1.72” while Mason City (Cerro Gordo County) observed 1.30”. A secondary cluster of showers and thunderstorms pushed into southwestern Iowa ahead of a low pressure system early on the 29th. Rain showers moved east through the state while later in the day the low’s attendant cold front propagated into western Iowa, firing strong to severe thunderstorms. The line of storms stretched into northwestern Iowa and swept across Iowa leaving behind measurable rainfall statewide. The line dissipated across eastern Iowa after daybreak on the 30th. Event totals were above 0.25 inch at most reporting stations with several stations observing at least an inch with Lamoni (Decatur County) measuring 1.92”.

Monthly precipitation totals ranged from 0.91” at Rock Rapids (Lyon County) to 7.24” at St. Ansgar (Mitchell County). Eastern and west-central Iowa stations observed above-average snowfall with below average totals at most Iowa stations. The preliminary statewide average snowfall was 0.9”, 0.7” below normal. Dubuque (Dubuque County) measured the state’s highest accumulation of 4.0”.

US Drought Monitor

Drought and abnormally dry conditions improved across Iowa through Iowa as much of eastern Iowa experienced wetter conditions. The initial drought depiction at the beginning of April showed 63% of the state covered in D0 (Abnormally Dry) to D2 (Severe Drought) conditions; the largest share was D0, which covered 38% of Iowa. Moderate Drought (D1) conditions encompassed nearly 23% of western, north-central and eastern Iowa with a 2% pocket of D2 coverage in western Iowa. A wet stretch of days through the middle of April helped aid in the removal of D0 in central Iowa as well as the D1 region in eastern Iowa. The final depiction of the month show improvement in the north-central D1 region as well as the D1-D2 region in the west; D2 remains in Monona, Woodbury and Plymouth counties, and has remained nearly constant over the month at less than three percent of the state.

Justin Glisan, Ph.D.
State Climatologist of Iowa
Iowa Dept. of Agriculture & Land Stewardship
Wallace State Office Bldg.
Des Moines, IA 50319
Telephone: (515) 281-8981
E-mail: Justin.Glisan@IowaAgriculture.gov

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