A significant rain event occurred late Friday into Saturday across extreme southeast Iowa. A slow moving mesoscale convective vortex (MCV) tracked over eastern Lee and Des Moines Counties and brought very heavy rain in a short amount of time.
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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 DVN wrote it up.
A significant rain event occurred late Friday into Saturday across extreme southeast Iowa. A slow moving mesoscale convective vortex (MCV) tracked over eastern Lee and Des Moines Counties and brought very heavy rain in a short amount of time. Rainfall amounts between 3 and 9 inches fell in less than 6 hours, which caused many stalled vehicles and several water rescues in Keokuk, Iowa. Other towns that received heavy rain were Fort Madison, Iowa and Burlington, Iowa.
A new daily rainfall record of 6.14 of rain occurred in Burlington, which broke the previous record of 2.03 back in 1903. This record also is the second highest daily rainfall on any given day in Burlington. The wettest day was 6.28 on June 29th, 1933.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Aug 4, 11:54 PM CST, 2 hours 21 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 1254 AM CDT Sat Aug 5 2023 ...AVIATION UPDATE... .UPDATE... Issued at 953 PM CDT Fri Aug 4 2023 MCV looks to traverse near our southern counties overnight. Slow movement will allow repeated rounds of moderate/heavy rain and thunder on the north side in the deformation zone, and not out of question for 2 to 3+ inch totals with locally higher possible with persistent rounds of thunder. CAM signal has potential for several inches in or very near our far southern service area border. Have decided to issue a Flood Watch for our far southern row of counties given flooding reports upstream from earlier into NW/NC Missouri and slow evolution of MCV and persistent high PWAT fetch of nearly 2 inches. && .SHORT TERM...(This afternoon through Saturday) Issued at 102 PM CDT Fri Aug 4 2023 Key messages: 1. MCV moving through area will bring chances for storms to the area tonight, with best chances south of I80. 2. Quiet afternoon with subdued temps from cloud cover Saturday. Discussion: A mix of scattered low clouds ahead of an MCV and high clouds associated with said MCV led to filtered sun today. This helped to keep temperatures slightly cooler than forecast. Dewpoints remained in the upper 60s to low 70s across the area. This MCV will drive the weather in the short term. Short term guidance has coalesced around the MCV firing convection late this afternoon and mostly overnight as the H85 jet kicks in. Showers and storms will ramp up tonight across the southern 1/2 of the CWA, proving much needed rain to this area. PWATs are forecast to be near or above 2 inches providing plentiful moisture for heavy rain. While we remain in the moist air, surface temperatures are cooler than south of the area, leading to lower CAPE across the area. The lower CAPE means that we won't see all that good convection and while ingredients are there for heavy rain, think that most of the area could see stratiform rain with the exception of the far south. CAMs and Global models both predict areas that could see 2-3 inches of rain tonight. The question is where that occurs. Watching CAMs through the evening and watching initial convection should help us determine if the 2-3 inch band is in our south or further south. I have pretty high confidence that this setup produces a band of heavy rain somewhere, where is still the question. Post storms/showers, cloud cover could help keep temps lower. Flow around the MCV could bring a surge of drier air into the area tonight, especially across the northern CWA. CAMs depict this, so with lower temps and potentially drier air, tomorrow may feel decent if that materializes. SPC has some portions of the area in a marginal risk for tomorrow. That is associated with later in the afternoon and evening and out of the short term period. .LONG TERM...(Saturday night through Friday) Issued at 218 PM CDT Fri Aug 4 2023 Key messages: 1. Thunderstorms are expected to begin the period, these storms will affect the weather Sunday. 2. Severe weather possible Sunday. 3. A break from the storm chances and humidity early next week, before active weather pattern returns as early as Wednesday. , outside of a bout of gustiness tied to the lake enhanced boundary passing tonight. A weekend full of mesoscale driven convection remains before a wave moves through the area Sunday. Guidance has had a hard time with this wave. Unfortunately, this means that impacts from the wave differ widely. At the current time, a slower storm system looks likely. This means that the wave will approach our area near peak heating. The current SPC marginal looks to be too fast as the wave will start affecting the area after 12z. Where this peak heating occurs is contingent on where the overnight convective debris exists to start the day. Anywhere where we are clear would likely mean a boundary surging north and a threat for strong to severe storms in the afternoon. We need to nail down this timing better with later forecasts. At the current time, it appears that the best area for severe storms will be south of I80. This area will be closer to the better moisture and lift ahead of the wave. Deep layer shear is good for updraft organization. Locally backed surface winds, could enhance a tornado threat as well. The NAMnest has a line of storms moving south of I80 during the day. This would likely result in severe winds in this scenario. All that said a lot has to happen for this to happen, the main story for Sunday is that conditions are favorable severe weather. Sunday night-Tuesday night...breezy northwest winds to advect in a cooler, less humid airmass and mostly dry conditions. Winds could gust over 30 mph at times on Monday with afternoon highs struggling to reach 80 degrees. Some wrap around showers may also be possible across northern IL on Monday. Slightly warmer conditions will be seen Tuesday area-wide, with highs in the lower 80s. Wednesday On...upper air pattern returns to semi-zonal with increasing temps and humidity through the rest of the work week. Latest ensemble and deterministic guidance widely varies on timing another strong wave and subsequent chances of storms to the region. Still way too early to determine severe risk, but it may be something to monitor in later forecasts. Temperatures will be near normal, with readings in the 80s and lows in the lower 60s each day. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1245 AM CDT Sat Aug 5 2023 A period of rain with embedded thunder will impact BRL overnight leading to occasional MVFR/IFR ceilings and visibilities. Light rain may make it up to MLI for a brief time with MVFR ceilings possible. For Saturday, expect a return to VFR conditions and mainly dry conditions. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Flood Watch until 10 AM CDT this morning for Lee. IL...Flood Watch until 10 AM CDT this morning for Hancock-McDonough. MO...Flood Watch until 10 AM CDT this morning for Clark-Scotland. && UPDATE...McClure SHORT TERM...Gibbs LONG TERM...Gibbs/Gross AVIATION...Uttech
Hazardous Weather Outlook National Weather Service Quad Cities IA IL 1007 PM CDT Fri Aug 4 2023 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-060315- Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson- Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson- Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll- Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson- Warren-Hancock-McDonough-Scotland-Clark- 1007 PM CDT Fri Aug 4 2023 This Hazardous Weather Outlook is for portions of north central Illinois...northwest Illinois...west central Illinois...east central Iowa...northeast Iowa...southeast Iowa and northeast Missouri. .DAY ONE...TONIGHT Showers and thunderstorms are expected into early Saturday morning, mainly across southeast Iowa, northeast Missouri and west central Illinois. Heavy rain is likely, and a Flash Flood Watch is in effect for portions of northeast Missouri and west central Illinois where repeated storms could produce rainfall amounts of 2 to 4 inches and a threat for flash flooding. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY Thunderstorms are expected Saturday and Sunday, with strong to severe storms possible. A Marginal Risk for severe weather is outlooked for Saturday south of a line from Belle Plaine, Iowa to Macomb, Illinois. Damaging wind and heavy rain will be possible. Another Marginal Risk for severe weather is forecast on Sunday along and east of a line from Dubuque, Iowa to Burlington, Iowa. A Slight Risk for severe weather is possible along and east of a Princeton, Illinois to Rockford, Illinois line. Large hail, damaging wind, and heavy rain will be possible. .SPOTTER INFORMATION STATEMENT... Please report rainfall amounts over 1 inch or any unusual or significant flooding issues.
Special Weather Statement
National Weather Service Quad Cities IA/IL
1247 AM CDT Sat Aug 5 2023
IAZ098-099-ILZ034-MOZ009-010-050630-
Hancock IL-Van Buren IA-Lee IA-Clark MO-Scotland MO-
1247 AM CDT Sat Aug 5 2023
...Slow-moving thunderstorms will impact portions of northern
Hancock, southeastern Van Buren, southwestern Lee, northern Clark and
northeastern Scotland Counties through 130 AM CDT...
At 1245 AM CDT, Doppler radar was tracking slow-moving thunderstorms
along a line extending from Memphis to near Colmar. Movement was
northeast at 30 mph.
HAZARD...Winds in excess of 40 mph and heavy rain.
SOURCE...Radar indicated.
IMPACT...Gusty winds could cause minor tree limb damage and blow
around unsecured objects.
Rainfall amounts around 1 inch have fallen and an additional 1 to 2
inches of rain are possible.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is occurring and may lead to localized flooding.
Do not drive your vehicle through flooded roadways.
If the heavy rain continues, a flash flood warning may be needed.
&&
LAT...LON 4061 9096 4035 9091 4040 9224 4060 9227
TIME...MOT...LOC 0545Z 202DEG 24KT 4047 9216 4039 9096
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
GrossPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
1251 AM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1230 AM Flash Flood Kahoka 40.42N 91.72W
08/05/2023 Clark MO Law Enforcement
Several streets are under water in town near
Hwy 81 and West Cedar St.
&&
GROSSPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
213 AM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0200 AM Flash Flood Kahoka 40.42N 91.72W
08/05/2023 Clark MO Law Enforcement
Four stalled vehicles reported in town and 1
water rescue was needed east of Kahoka on
County Rd 182 southeast of town.
&&
GROSSSpecial Weather Statement
National Weather Service Quad Cities IA/IL
234 AM CDT Sat Aug 5 2023
IAZ089-099-ILZ025-034-035-050830-
Henderson IL-McDonough IL-Hancock IL-Des Moines IA-Lee IA-
234 AM CDT Sat Aug 5 2023
...Slow-moving thunderstorms will impact portions of southwestern
Henderson, southwestern McDonough, Hancock, southeastern Des Moines
and central Lee Counties through 330 AM CDT...
At 234 AM CDT, Doppler radar was tracking slow-moving thunderstorms
along a line extending from near West Point. Movement was northeast
at 25 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Strong winds could break small tree limbs and blow around
unsecured objects.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is occurring and may lead to localized flooding.
Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4020 9131 4066 9150 4088 9104 4028 9072
4028 9091 4019 9091
TIME...MOT...LOC 0734Z 226DEG 24KT 4066 9142 4020 9122
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
GrossPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
240 AM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0237 AM Rain 3 WSW Wayland 40.38N 91.63W
08/05/2023 M5.82 inch Clark MO Mesonet
Rainfall in past 3 hours.
&&
GROSSPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
255 AM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0244 AM Tstm Wnd Gst Keokuk 40.41N 91.41W
08/05/2023 E55 MPH Lee IA Trained Spotter
&&
GROSSThe Quad Cities radar (KDVN), 150 km away, was scanning. The volume nearest the first event began at 08:13 UTC.
2 flash flood. Local standard time, as filed.
Law Enforcement reported several stalled vehicles and water rescues by first responders in town in the past 2 to 3 hours. There was 4 to 5 feet of water reported on many roads and streets.
The Emergency Manager reported that a drainage ditch was out of its banks, causing flooding. The time of the event was when the picture was taken.
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: 1129569, 1129570.