Rainfall early in the month across portions of southwest and south central Iowa helped to improve drought conditions.
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.
Rainfall early in the month across portions of southwest and south central Iowa helped to improve drought conditions.
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 Jul 31, 10:33 PM CST, 1 hour 27 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1133 PM CDT Mon Jul 31 2023 ...Updated for the 06z Aviation Discussion... .DISCUSSION.../Tonight through Monday/ Issued at 236 PM CDT Mon Jul 31 2023 Key messaging highlights: * Periodic chances for showers and storms through the weekend. * Severe weather potential low overall, but a few periods of isolated heavy rains are possible * No extremes, but seasonally high temps and/or humidity through the work week Our pattern will undergo some changes through the period with a gradual transition from central CONUS ridging to more zonal flow and northern stream influences. This will keep our weather somewhat active, but without any strong signal toward severe weather. Although there may be a few windows where strong-severe storms may occur with bursts of more favorable effective shear, the thermal profiles aren't overly favorable with no appreciable instability return. Looking into tonight, the MO Valley genesis region will again be the area of concern with some frontogenesis and moisture convergence along the persistent 1-3km baroclinic zone. Our current isolated showers south should wane shortly, with additional chances south and west into early Tue morning and even better just to the south. Light winds, persistent clouds, and fairly low afternoon temp/dewpoint spreads have also led to the introduction of some fog mention south. These forcing mechanisms and the baroclinic zone do creep farther north and east by Tue night into Wed morning however, increasing our chances for convection during the period. While effective shear would support stronger storms, the instability remains fairly low diminishing severe potential somewhat. There isn't a great consensus, with some solutions staying south, but some deterministic runs and ensemble members do boost the heavy rain parameter space north into IA with precipitable water values 2+" and warm cloud depths 4-4.5km suggesting isolated efficient rains and heavy rainfall would be possible. Beyond this there may be a relative lull later Wed into the end of the work week, but models are suggesting some northern stream short wave maturation around Fri or Sat with a leading surge of theta-e advection aloft followed by the passage of a surface system and either a front or inverted trough providing additional low level focus. This leads to another uptick in storm chances over that window. Temperatures are expected to remain at or just above seasonal normals through the period with little strength in return flow and either steady or diminishing heights. However, while not at extremes, dewpoints should be persistent in the 60s or lower 70s at times keeping the sensible perception of humidity somewhat high. && .AVIATION.../For the 06Z TAFS through 06Z Tuesday night/ Issued at 1133 PM CDT Mon Jul 31 2023 VFR conditions are expected to remain into the overnight hours for the majority of the terminals. The signal for areas of patchy fog has increased, likely confined to southern Iowa after 09z and continuing through sunrise before dissipating. Lower visibilities will be the main impact, with best chances over KDSM and KOTM. With clouds expected to move across the state during the period, this may limit overall fog coverage so will be watching conditions closely. Otherwise, rain and storm chances have overall been pushed slightly further south, limiting the potential for any activity to impact the southern terminals. Will continue to monitor trends, but overall not expecting any major impacts through the forecast period. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && DISCUSSION...Small AVIATION...Bury
Hazardous Weather Outlook National Weather Service Des Moines IA 252 PM CDT Mon Jul 31 2023 IAZ004>007-015>017-023>028-033>039-044>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-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- 252 PM CDT Mon Jul 31 2023 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight Scattered thunderstorms are expected over southwest Iowa late overnight. Severe weather is not expected. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Periodic chances for showers and thunderstorms continue through Friday. Threat of severe weather is generally low, but a few stronger storms with locally heavy rain, hail, and gusty winds are possible Tuesday into Wednesday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated. Hagenhoff
The national radar mosaic for the moment the first event began.
3 drought. Local standard time, as filed.
Several rainfall events helped to improve drought and hydrologic conditions across Clarke County in early August.
Several rainfall events helped to improve drought and hydrologic conditions across Decatur County in early August.
Several rainfall events helped to improve drought and hydrologic conditions across Cass County in early August.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2023Every state in 2023This day in weather historyWarnings in Iowa, August 2023
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: 1123334, 1123335, 1123336.