Drought conditions persisted in southern Iowa for much of the month although there were a few significant rainfall events that helped alleviate the drought in a few areas.
Every event with a place to put it; 14 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.
Drought conditions persisted in southern Iowa for much of the month although there were a few significant rainfall events that helped alleviate the drought in a few areas.
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, 10:56 PM CST, 1 hour 4 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1156 PM CDT Thu Aug 31 2017 .SHORT TERM.../Tonight through Friday/ Issued at 200 PM CDT Thu Aug 31 2017 Stubborn stratus has been the main forecast challenge on the short term side today. The band of lower ceilings resides in the vicinity of a shallow backdoor front that is slowly sagging southwest. High-res models suggest the potential for a few showers and storms late this afternoon and early evening near the frontal axis in central Iowa. Latest RAP analysis indicates 1000-1500 J/kg of MLCAPE and weak theta-e convergence in the 925-850mb layer, but the spatial coverage of any convective activity will be sparse at best as favorable upper level kinematic support remains well west of the forecast area. Areas of fog are possible again early Friday morning, mainly from north central through southeast Iowa. NAM/GLAMP favor fog, while the HRRR-TL/SREF/RAP camps remain clear. Upwind obs show a slightly cooler and drier air mass filtering behind the front, which may be enough to limit the fog potential tonight. Any mention of fog has been left out of the grids for now due to low confidence. .LONG TERM.../Friday night through Thursday/ Issued at 200 PM CDT Thu Aug 31 2017 Primary focus of the long term period is temperatures with a warm up expected through the weekend followed by a strong cold frontal passage early next week. Weak ridging aloft will lead to quiet conditions through the weekend. Low level southerly flow ramps up by Sunday as an upper level trough digs southeast into the northern Rockies. Strong warm air advection pushes 850mb temps above 20C for Sunday and Monday with afternoon highs in the mid to upper 80s. Would not be surprised to see some places in southern Iowa break into the 90s. Euro and GFS have come into much better temporal agreement with the upper level low as it digs south and becomes highly amplified. This will shove a strong cold front through the area Monday night. Isolated to scattered storms are possible with the frontal passage, but the extent and strength of the activity will be limited by dry air and weak instability. Expecting highs to drop back into the 60s and 70s for the middle of the week. Overnight lows were adjusted a few degrees lower from the inherited Superblend to better match the lows favored by ECE/MEX guidance. This would be an early taste of fall as the Des Moines metro has not seen temperatures in the 40s since May. && .AVIATION.../For the 06Z TAFS through 06Z Friday night/ Issued at 1156 PM CDT Thu Aug 31 2017 Low clouds will persist across the western half of Iowa overnight while haze/light fog will persist in the east. This will produce VFR to MVFR conditions overnight with light east winds. Conditions will improve into Friday with widespread VFR conditions from mid morning onward through the remainder of the period. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...Martin LONG TERM...Martin AVIATION...Cogil
Hazardous Weather Outlook National Weather Service Des Moines IA 901 PM CDT Thu Aug 31 2017 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-011100- 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- 901 PM CDT Thu Aug 31 2017 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...Friday through Wednesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated.
Special Weather Statement National Weather Service Des Moines IA 1224 AM CDT Fri Sep 1 2017 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-011000- 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- Including the cities of Estherville, Algona, Forest City, Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha, Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison, Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, Marshalltown, Tama, Toledo, Traer, Dysart, Gladbrook, Audubon, Exira, Guthrie Center, Panora, Bayard, Casey, Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Atlantic, Greenfield, Stuart, Adair, Fontanelle, Winterset, Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, Oskaloosa, Corning, Creston, Osceola, Chariton, Albia, Ottumwa, Bedford, Lenox, New Market, Mount Ayr, Lamoni, Leon, Corydon, Seymour, Allerton, Humeston, Centerville, and Bloomfield 1224 AM CDT Fri Sep 1 2017 ...SMOKE ACROSS IOWA REDUCING VISIBILITY... Smoke from Canadian forest fires has made its way into eastern Iowa tonight and will continue to drift westward through morning. Visibility from the smoke has dropped to between 2 and 5 miles. The latest Air Quality Index provided by the Iowa DNR suggests unhealthy conditions for portions of eastern Iowa. FAB
The national radar mosaic for the moment the first event began.
14 drought. Local standard time, as filed.
Severe drought conditions clipped far southeast Adair county due to acute short term dryness.
Severe to extreme drought conditions persisted in much of Madison county due to acute short term dryness.
Severe to extreme drought conditions persisted in much of Warren county due to acute short term dryness.
Severe to extreme drought conditions persisted in much of central and southern Marion county due to acute short term dryness.
Severe drought conditions persisted in across far southwest Mahaska county due to acute short term dryness.
Severe to extreme drought conditions persisted in much of central and eastern Union county due to acute short term dryness.
Extreme drought conditions persisted across all of Clarke county in September due to acute short term dryness.
Severe to extreme drought conditions persisted across Lucas county in September due to acute short term dryness.
Severe to extreme drought conditions persisted across Monroe county in September due to acute short term dryness.
Severe drought conditions persisted in far northeast Ringgold county in September due to acute short term dryness.
Severe drought conditions persisted across much of northern Decatur county in September due to acute short term dryness.
Severe drought conditions persisted across northern and central Wayne county in September due to acute short term dryness.
Severe drought conditions persisted across northern and central Appanoose county in September due to acute short term dryness.
Severe drought conditions persisted across northern and central Davis county in September due to acute short term dryness.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2017Every state in 2017This day in weather historyWarnings in Iowa, September 2017
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: 766015, 766016, 766017, 766018, 766019, 766020, 766021, 766022, 766023, 766024, 766025, 766027, 766028, 766029.