As a cold front moved through the region, showers and storms developed. One area of storms produced very heavy rainfall and flash flooding over portions of Lincoln County.
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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.
As a cold front moved through the region, showers and storms developed. One area of storms produced very heavy rainfall and flash flooding over portions of Lincoln County.
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 27, 4:56 AM CST, 2 hours 54 minutes earlier.
Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 556 AM CDT Mon Jul 27 2020 .SHORT TERM... (Through Late Tuesday Afternoon) Issued at 402 AM CDT Mon Jul 27 2020 Scattered showers and storms are developing and moving through northeast and central MO and west central IL early this morning south of a cold front extending from WI southwest through southern portions of Nebraska and Iowa. This cold front will drop southward through our forecast area today and tonight as the upper level trough over the Northern Plains deepens as it moves eastward through the Great Lakes region. The showers and storms will shift southward through our area with the best coverage across central and southeast MO and southwest IL by this afternoon, and across southeast MO and southwest IL tonight. Although the wind shear looks too weak for organized severe storms, high values of precipitable water and relatively deep warm cloud depths will result in locally heavy rainfall, mainly this afternoon across central and southeast MO and southwest IL. High temperatures will not be as hot today, particularly across northeast and central MO and west central IL, mainly due to the cloud cover and precipitation. By 12Z Tuesday the cold front should be near the MO and AR border with slightly below normal low temperatures for northeast and central MO and west central IL tonight along with much lower humidity/surface dew points. Any precipitation on Tuesday should be confined to parts of southeast MO and southwest IL, just north of the front. GKS .LONG TERM... (Tuesday Night through Sunday) Issued at 402 AM CDT Mon Jul 27 2020 Just a brief break in the precipitation potential Tuesday night, then convection will spread eastward into central and eastern MO on Wednesday ahead of an approaching upper level trough. The front will lift back northward as a warm front Wednesday night with convection expected along and just north of this front. The active wet weather pattern will continue for at least the rest of the work week with below normal temperatures as a slow moving upper level trough drops southeastward from the northern Plains and into the central Plains with weak surface lows/waves developing along the nearly stationary front across southern portions of MO and IL. High temperatures by Friday may be up to 10 degrees below normal. On Sunday the upper level trough should finally shift east of the forecast area gradually ending the threat for precipitation, but continuing the below normal temperatures through the remainder of the weekend due to low upper level heights and northerly surface winds. GKS && .AVIATION... (For the 12z TAFs through 12z Tuesday Morning) Issued at 538 AM CDT Mon Jul 27 2020 A cold front extending from WI southwest through southern portions of Iowa and Nebraska will move southeastward through the taf sites today. Periods of showers and storms can be expected today and early this evening at the taf sites. The prevailing cloud ceiling will drop into the MVFR category later this morning in UIN and COU and continue into the afternoon. Southwest winds will veer around to a northwest direction this afternoon. SPECIFICS FOR KSTL: A cold front extending from WI southwest through southern portions of Iowa and Nebraska will move southeastward through STL this afternoon. Periods of showers and storms can be expected today and early this evening. Southwest winds will veer around to a northwest direction this afternoon. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service Saint Louis MO 437 AM CDT Mon Jul 27 2020 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-280945- 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- 437 AM CDT Mon Jul 27 2020 This Hazardous Weather Outlook is for portions of eastern and central Missouri as well as west central and southwest Illinois. .DAY ONE...Today and tonight. Thunderstorms likely today with a chance of thunderstorms tonight. Locally heavy rainfall possible, mainly this afternoon across central and southeast Missouri and southwest Illinois. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. There is a chance of thunderstorms for parts of our area each day of the period. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated through tonight. GKS
The St Louis radar (KLSX), 43 km away, was scanning. The volume nearest the first event began at 13:50 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. Numerous roads were flooded including portions of Highway 47 between Troy and Hawk Point.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2020Every state in 2020This day in weather historyWarnings in Missouri, July 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: 909324.