An upper level shortwave brought several rounds of showers and storms. Some of the storms dumped up to 4 inches of rain in a short amount of time causing flash flooding.
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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 LSX wrote it up.
An upper level shortwave brought several rounds of showers and storms. Some of the storms dumped up to 4 inches of rain in a short amount of time causing flash flooding.
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 St. Louis, MO wrote its last area forecast discussion before the first event at Jul 12, 1:15 PM CST, 45 minutes earlier.
Area Forecast Discussion National Weather Service Saint Louis MO 215 PM CDT Mon Jul 12 2021 .SHORT TERM... (Through Late Tuesday Night) Issued at 152 PM CDT Mon Jul 12 2021 The upper level low that has brought showers to the region the past few days will finally progress north/northeast tonight, with the trailing shortwave axis and surface low pressure moving east of the CWA by tomorrow afternoon. The result will be a decrease in rain chances with dry weather now expected on Tuesday. Still expect a blanket of stratus to redevelop in the wake of the system tonight with low ceilings lifting and scattering during the late morning and afternoon on Tuesday. Temperatures will be slightly warmer on Tuesday with the lack of rain showers and decreasing clouds during the afternoon, but still around 5 degrees below normal. CVKING .LONG TERM... (Wednesday through Next Monday) Issued at 152 PM CDT Mon Jul 12 2021 An active storm track is forecast to develop across the upper Midwest and into the western Great Lakes on Wednesday and Thursday with a dry and warmer period of weather across the lower Missouri and middle Mississippi river valleys. This looks to be short-lived though as the latest model guidance brings that active pattern back south Thursday night and Friday as a shortwave moves southeast across the region. Greater uncertainty exists heading into next weekend, but a parade of shortwaves interacting with a nearly stationary frontal boundary looks to support likely PoPs again next wet weekend. After a few days of temperatures near or slightly above normal on Wednesday and Thursday, increased cloud cover and precipitation will suppress temperatures heading into next weekend. CVKING && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1154 AM CDT Mon Jul 12 2021 IFR stratus currently blankets west central Missouri through northeast Missouri and into central Illinois with MVFR cumulus cloud cover south of this area from the Ozarks through St. Louis and into southwest Illinois. Scattered showers continue to rotate cyclonically across the region, locally reducing visibility to IFR. The low pressure center that is responsible for this weather will slowly move east and exit the area tonight. Stratus is expected again tonight in the wake of this system but showers should diminish shortly after sunset. Light southerly winds ahead of the low pressure system south of I-70 will shift to the west/northwest in the wake of the system, similar to those currently found in northern Missouri. SPECIFICS FOR KSTL: A few showers are possible this afternoon near the terminal and these could locally reduce visibility. The current southwest wind direction will become west and then northwest as the low pressure center moves farther to the east. IFR ceilings are expected tonight and tomorrow morning as stratus builds back into the area. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service Saint Louis MO 224 PM CDT Mon Jul 12 2021 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-131930- Adams IL-Audrain MO-Bond IL-Boone MO-Brown IL-Calhoun IL-Callaway MO- Clinton IL-Cole MO-Crawford MO-Fayette IL-Franklin MO-Gasconade MO- Greene IL-Iron MO-Jefferson MO-Jersey IL-Knox MO-Lewis MO-Lincoln MO- Macoupin IL-Madison IL-Madison MO-Marion IL-Marion MO-Moniteau MO- Monroe IL-Monroe MO-Montgomery IL-Montgomery MO-Osage MO-Pike IL- Pike MO-Ralls MO-Randolph IL-Reynolds MO-Saint Charles MO- Saint Clair-Saint Francois MO-Saint Louis City MO-Saint Louis MO- Sainte Genevieve MO-Shelby MO-Warren MO-Washington IL-Washington MO- 224 PM CDT Mon Jul 12 2021 This Hazardous Weather Outlook is for portions of eastern and central Missouri as well as west central and southwest Illinois. .DAY ONE...Tonight. Isolated thunderstorms may produce locally heavy rainfall this evening. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Thunderstorms are possible again Thursday night through Sunday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not needed. CVKING
The St Louis radar (KLSX), 69 km away, was scanning. The volume nearest the first event began at 20:00 UTC.
1 flash flood. Local standard time, as filed.
Up to four inches of rain fell in a short amount of time causing flash flooding. Several roads were flooded including at the intersection of Highways E and O north of Olney.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2021Every state in 2021This day in weather historyWarnings in Missouri, July 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: 975364.