Slightly above normal temperatures and persistent dryness during the summer led to the expansion of severe drought conditions in portions of western Iowa in late August.
Every event with a place to put it; 2 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.
Slightly above normal temperatures and persistent dryness during the summer led to the expansion of severe drought conditions in portions of western Iowa in late August.
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 24, 10:44 PM CST, 1 hour 16 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1144 PM CDT Mon Aug 24 2020 .DISCUSSION.../Tonight through Monday/ Issued at 206 PM CDT Mon Aug 24 2020 .Overview...The main weather theme through Thursday will be hot and dry conditions. Thereafter, cooler weather will return with a chance of storms late this week and another perhaps higher chance sometime early next week. .Details...Mid-level high pressure is centered over the Four Corners region with mid-level ridging over the western into the central US. This will keep conditions hot with highs generally in the middle 90s and any storms tracking north of our area through Thursday. While heat indices will fall short of our criteria, the short duration heat advisory for this afternoon will aid in consistent and seamless messaging. Future days will have the same challenge as today with regards to a headline or not. Nudgers towards no heat headline outlined here and in the following sentences include: boundary layer mixing, breezier winds, near surface moisture sources, and 'cool' overnight temperatures. NAM/GFS forecast soundings continue to show a deep boundary layer with depths of 4000 to 5000 feet in the afternoon through midweek. This will result in dewpoints lowering through the day as drier air mixes to the surface. Further, winds at the top of the boundary layer are between 20 and 25 knots and will make for breezier surface winds through the mid to late morning hours and into the afternoon. There will also be a lack of near surface moisture largely in part due to the ongoing drought conditions and to some degree due to damaged/destroyed crops not providing evapotranspiration. Overnight lows the next few nights in the upper 60s to around 70 degrees will also offer a reprieve from the daytime heat. There will finally be a front that will be pushed slowly southward through the state Thursday night through Friday night. Rain and storm chances may accompany the front, but only the latest ECMWF offers hope for widespread precipitation. While the moisture from the remnants of Laura will be pushing through the Ozarks late this week, it looks like the front will not interact with this moisture until it is passed through the state. For the weekend into early next week, temperatures will fall back into the low 80s if not upper 70s. The deterministic models (CMC, GFS, ECMWF) are largely void of QPF this weekend. However, there is enough spread in the ensemble members from these models to have low chance PoPs in the National Blend starting late Saturday night through Sunday. Being on day 6 or 7, was not going to try to pick the 'right' model, but could see the weekend being drier than currently forecast. The next highest chance for rain and storms after Thursday will likely come early next week as both the GFS and ECMWF dig a trough into the northern Plains with a cold front pushing through the region. && .AVIATION.../For the 06Z TAFS through 06Z Tuesday night/ Issued at 1144 PM CDT Mon Aug 24 2020 A few very isolated showers/storms are possible around MCW in the next several hours, but probability/duration of any impacts so low it is not mentioned in the outgoing TAFs. Also a small chance of fog formation toward sunrise Tuesday morning, again in the north around FOD/MCW, but again probability too low for TAF advertisement. Otherwise, and especially after 12Z Tuesday, no precipitation/obscurations or aviation impacts anticipated for the remainder of the TAF period and beyond. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && DISCUSSION...Ansorge AVIATION...Lee
Hazardous Weather Outlook National Weather Service Des Moines IA 715 PM CDT Mon Aug 24 2020 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-260015- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Black Hawk-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- 715 PM CDT Mon Aug 24 2020 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday There is a chance for thunderstorms Thursday into Friday. The severe weather threat will be better determined in the coming days. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. CURTIS
The national radar mosaic for the moment the first event began.
2 drought. Local standard time, as filed.
Slightly above normal temperatures and lack of rainfall led to expansion of severe drought conditions into Emmet county in late August.
Slightly above normal temperatures and lack of rainfall led to expansion of severe drought conditions into Adams county in late August.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2020Every state in 2020This day in weather historyWarnings in Iowa, August 2020
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: 915656, 915657.