Severe drought continued in portions of Northern Iowa into early September. However, widespread generous rainfall helped to improve conditions by the end of the first week of the month.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS DMX wrote it up.
Severe drought continued in portions of Northern Iowa into early September. However, widespread generous rainfall helped to improve conditions by the end of the first week of the month.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before the first event at Aug 31, 10:59 PM CST, 1 hour 1 minute earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1159 PM CDT Tue Aug 31 2021 .DISCUSSION.../Tonight through Tuesday/ Issued at 237 PM CDT Tue Aug 31 2021 Take Home Points: *Clearing skies/conditions rest of today *Generally pleasant conditions through mid-week *Showers/thunder returns Thursday afternoon through Friday *Likely quiet weekend and uncertain shower/storm chances early next week Discussion: After an active Monday evening and overnight, showers and storms consistently trended downward as they slowly trekked eastward through the day today. By mid afternoon, shower/storm activity had moved primarily into areas of eastern and southeast Iowa. The mid-upper level shortwave driving much of the activity will continue to slowly slide east/southeast and lingering/festering activity too will follow it. In the wake of the activity, mostly cloudy skies will slowly dissipate through the evening, eventually yielding mostly clear conditions. With the robust activity this morning riding roughly down the Missouri River, the surface and mid level boundaries have settled across portions of Nebraska, Kansas, and Missouri, along a line from O'Neill, NE to Kansas City to near Jefferson City, MO. That in mind, any activity tonight should be in/around the aforementioned areas as the LLJ picks up, keeping much, if not all, of the state dry. Through the middle of the week, broad surface high pressure sliding down the western Great Lakes region and upper level ridging sliding into the Upper Plains will work in tandem to keep sensible weather quiet and comfortable. Expect highs to remain in the upper 70s to low 80s for most and the more humid conditions over far western Iowa. Ending the week, a western Canada upper trough will work into the Canadian Plains and begin squash upper level in the region. More pertinent to the Thursday-Friday time frame will be a shortwave ejecting out of the southwest US and subsequent surface low development. Synoptic guidance remains in fair agreement of surface low track initially to our NW Thursday PM, then shifting eastward into Friday, resulting in widespread opportunity for showers/storms. Regarding the potential for strong to severe threats, conditions continue to look to reside on the lower end with limited favorable CAPE/shear parameter space depictions. As the activity exits and subsides Friday, a shortwave rounding the fringes of the Canadian upper low may provide another round of showers/storms Friday PM/overnight, but again looks to be limited in its overall impact. The remainder of the weekend then will be dominated by NW upper flow and building surface high pressure. Early next week the region will continue to be under the influence of NW flow and precipitation chances will be at the whim of varied shortwave timing. Throughout this time frame, end of this week into early next week, temperatures will remain seasonable to seasonable cool with highs in the 70s to lower 80s for much of the area. && .AVIATION.../For the 06Z TAFS through 06Z Wednesday night/ Issued at 1158 PM CDT Tue Aug 31 2021 Very spotty MVFR ceilings linger across southern and eastern sections at 06z, but are not expected to impact nearby TAF sites. There is some potential for brief MVFR fog toward daybreak as well, but this potential mainly appears to be south and west of TAF sites. Thus VFR conditions will be depicted until trends suggest otherwise with persistent light winds, mainly from the east. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && DISCUSSION...Curtis AVIATION...Small
Hazardous Weather Outlook National Weather Service Des Moines IA 248 PM CDT Tue Aug 31 2021 IAZ004>007-015>017-023>028-033>038-044>050-057>062-070>075- 081>086-092>097-012000- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Crawford-Carroll-Greene-Boone- Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek- Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas- Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis- 248 PM CDT Tue Aug 31 2021 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorms are expected at times from late Thursday through Friday. The threat of severe weather is uncertain at this time. .SPOTTER INFORMATION STATEMENT... Spotters will not be needed. IAZ039-012000- Black Hawk- 248 PM CDT Tue Aug 31 2021 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight A Flood Warning is in effect for the area. Please refer to the National Weather Service website at weather.gov/desmoines for further details. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorms are expected at times from late Thursday through Friday. The threat of severe weather is uncertain at this time. .SPOTTER INFORMATION STATEMENT... Spotters will not be needed.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
832 PM CDT TUE AUG 31 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1251 AM TSTM WND DMG LEWIS 41.31N 95.09W
08/31/2021 CASS IA TRAINED SPOTTER
POWER LINES DOWN IN LEWIS. DELAYED REPORT.
&&
BSSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
848 PM CDT TUE AUG 31 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0800 PM HEAVY RAIN 6 ESE GRISWOLD 41.20N 95.03W
08/31/2021 M4.00 INCH CASS IA TRAINED SPOTTER
RAINFALL OVER THE PAST 24 HOURS.
&&
BSSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
859 PM CDT TUE AUG 31 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1235 AM TSTM WND DMG GREENFIELD 41.31N 94.46W
08/31/2021 ADAIR IA TRAINED SPOTTER
MINOR TREE DAMAGE. DELAYED REPORT.
&&
BSSThe national radar mosaic for the moment the first event began.
3 drought. Local standard time, as filed.
Severe drought conditions were ongoing across Emmet county to begin the month. However, decent rainfall during the first week of September led to improved conditions across the county with severe drought ending.
Severe drought conditions were ongoing across Kossuth county to begin the month. However, decent rainfall during the first week of September led to improved conditions across the county with severe drought ending.
Severe drought conditions were ongoing across Palo Alto county to begin the month. However, decent rainfall during the first week of September led to improved conditions across the county with severe drought ending.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2021Every state in 2021This day in weather historyWarnings in Iowa, September 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 981576, 981577, 981578.