Showers and storms developed ahead of a cold front. Some of the storms produced very heavy rainfall that caused 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.
Showers and storms developed ahead of a cold front. Some of the storms produced very heavy rainfall that caused 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 Jun 22, 1:44 PM CST, 2 hours 16 minutes earlier.
Area Forecast Discussion National Weather Service Saint Louis MO 244 PM CDT Mon Jun 22 2020 .SHORT TERM... (Through Late Tuesday Night) Issued at 233 PM CDT Mon Jun 22 2020 Showers and thunderstorms have focused along a south/southwest to north/northeast axis of surface convergence. This axis should slowly move eastward over the next several hours. However, the synoptic cold front around 0000 UTC will likely be near a KCOU>>KUIN line. This front likely will attempt to become the main focus for storms during the late evening into the early overnight hours. However, it likely will enter an environment at least partially worked over by ongoing thunderstorms. Therefore, these storms should weaken as they continue southeastward along the cold front. Some of the storms through early evening may be strong to severe, with damaging winds and large hail the main threats. The coverage of storms along this front should also lessen tonight as low-level convergence weakens and stronger forcing for mid/upper level ascent slides eastward out of the area. The front should exit the southeastern CWA around 0900 UTC give or take a couple of hours. Behind the front, cooler and more stable air will infiltrate the region cutting off any chances of showers or storms. Mostly dry weather is favored on Tuesday, but did add the mention of isolated showers as a weak secondary cold front slides through the area beneath cyclonic flow aloft. Left thunder mention out as the instability tomorrow afternoon as model soundings suggest updrafts will be capped by a strong temperature inversion between 775 and 675 hPa. The vast majority of the area though should stay dry and even the isolated shower activity likely would be light in nature. Therefore, the main thing people will notice for Tuesday will be the cooler and less humid airmass now in place over the mid-Mississippi Valley. Look for high temperatures to range from the upper 70s to low 80s across the area, or about 5 degrees below normal for the date. Decreasing cloudiness is expected Tuesday night as the diurnal cumulus dissipates by early evening. A mostly clear and seasonably cool night should be in store with forecast lows in the upper 50s to low 60s. Gosselin .LONG TERM... (Wednesday through Next Monday) Issued at 233 PM CDT Mon Jun 22 2020 (Wednesday - Thursday) Not much change in the upper air pattern for the middle of the work week as a closed mid/upper level low remains quasi-stationary over the Great Lakes. Seasonably cool and mostly dry conditions with low humidity should remain in place across our region as a result. An isolated shower or weak thunderstorm may be possible during the heat of each day, but by and large it looks dry. Temperatures likely will also moderate slightly each day as the airmass slowly modifies. By Thursday, highs in the mid to upper 80s are forecast for much of the area. (Thursday Night - Next Monday) A more active regime still looks possible toward the end of the work week and into next weekend as both the GEFS/EPS depict midlevel flow that becomes more zonal. At the surface, a warm front is forecast to slowly progress through the area Thursday night into Friday. This feature could help provide the focus for shower and thunderstorm development as a shortwave trough moves out of the south-central Plains. This warm front likely will make it north of the area by late Friday, before attempting to move southward as a cold front as another shortwave embedded within zonal flow aloft moves across. Uncertainty with the evolution of this frontal boundary this weekend is high and will have a big impact on sensible weather (precipitation chances and temperatures). Maintained PoPs slightly above climatology given these uncertainties for this period with a slight focus on the afternoon/evening hours each day. Temperatures should be above normal day and night, but specific highs especially are difficult due to the uncertainty with the frontal placement and its impacts to clouds and precipitation chances. For now, have generally upper 80s to low 90s each day with lows in the upper 60s to mid 70s. These values would be about 5 degrees above normal. Humidity should also be on the increase beginning on Friday so peak heat index values may approach 100 degrees. Gosselin && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1228 PM CDT Mon Jun 22 2020 Thunderstorm coverage is expected to increase over the next few hours, peaking between 2100 and 0000 UTC. Maintained a TEMPO group in at KUIN and the metro terminals as these airports have a better chance at seeing storms. Heavy downpours reducing visibility, gusty winds, and small hail are threats for any storm directly impacting an airport through early this evening. The threat for storms should end late this evening behind a cold front. Expect dry weather with VFR conditions with northwest winds around 10 knots. SPECIFICS FOR KSTL: Thunderstorms are expected to develop this afternoon in and around the terminal, with the best chances roughly between 2000 and 0100 UTC. Still looks likely that at least a storm directly impacts the terminal so maintained a TEMPO group. Any storm that does hit KSTL will be capable of heavy downpours with reduced visibility, gusty winds, and small hail. The threat for storms should subside by late this evening behind a cold frontal passage. Dry/VFR conditions are favored thereafter along with a northwest wind around 10 knots. Gosselin && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service Saint Louis MO 251 PM CDT Mon Jun 22 2020 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-232000- 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 IL-Saint Francois MO-Saint Louis City MO-Saint Louis MO- Sainte Genevieve MO-Shelby MO-Warren MO-Washington IL-Washington MO- 251 PM CDT Mon Jun 22 2020 This Hazardous Weather Outlook is for portions of eastern and central Missouri as well as west central and southwest Illinois. .DAY ONE...Tonight. Thunderstorms are likely across the area through early this evening. Some of the storms may be strong to severe with damaging winds and large hail the primary threats. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. There is a chance for thunderstorms across parts of the area Thursday through Sunday. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report any wind damage or hail to the National Weather Service. Gosselin
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
228 PM CDT MON JUN 22 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0224 PM HAIL 3 E CURRYVILLE 39.36N 91.30W
06/22/2020 E0.25 INCH PIKE MO PUBLIC
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
230 PM CDT MON JUN 22 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0215 PM HEAVY RAIN TRUXTON 39.00N 91.24W
06/22/2020 M0.70 INCH LINCOLN MO PUBLIC
0215 PM HEAVY RAIN 1 S TRUXTON 38.99N 91.24W
06/22/2020 E1.50 INCH LINCOLN MO PUBLIC
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
303 PM CDT MON JUN 22 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0245 PM HAIL 5 NNW BOWLING GREEN 39.40N 91.25W
06/22/2020 M0.50 INCH PIKE MO LAW ENFORCEMENT
5-10 MINUTES OF HAIL.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
338 PM CDT MON JUN 22 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0335 PM HEAVY RAIN 4 WSW VERSAILLES 39.85N 90.72W
06/22/2020 M1.50 INCH BROWN IL TRAINED SPOTTER
FELL IN HALF AN HOUR.
&&
MABThe Lincoln radar (KILX), 76 km away, was scanning. The volume nearest the first event began at 21:57 UTC.
1 flash flood. Local standard time, as filed.
Up to 4 inches of rain fell in a short amount of time causing flash flooding. Numerous roads in the Farmersville and Waggoner areas. Macoupin Creek is out of its banks in Farmersville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2020Every state in 2020This day in weather historyWarnings in Illinois, June 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: 905225.