A cutoff low helped to develop a round of afternoon thunderstorms. Some of the storms produced damaging winds.
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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.
A cutoff low helped to develop a round of afternoon thunderstorms. Some of the storms produced damaging winds.
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 May 25, 11:13 AM CST, 2 hours 32 minutes earlier.
Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1213 PM CDT Mon May 25 2020 .UPDATE... Issued at 1000 AM CDT Mon May 25 2020 The latest data streaming in continues to suggest we will see additional thunderstorm development this afternoon into early this evening. Latest water vapor imagery and objective analysis shows a weak shortwave embedded within the southerly mid-level flow over northern AR. This feature will spread northward today, helping to focus enough surface convergence to spark thunderstorms in a fairly uncapped environment. Today's setup is slightly different than yesterday's. Dewpoints this morning are generally 3-4 degrees cooler than they were this time yesterday morning. Consequently, instability is not forecast to be quite as strong this afternoon as it was yesterday, but will still be significant with MLCAPEs of 1500-2500 J/kg expected. That being said, deep-layer shear is expected to be slightly higher today (20-25 knots) which could lead to a bit better storm organization. Therefore, isolated severe storms are possible this afternoon, especially in Missouri where the better forcing and associated shear will be higher than in IL. While the airmass between 5-10k feet is much more moist than it was yesterday, precipitation loading may lead to isolated damaging wind gusts and some instances of hail to the size of quarters are possible in the more organized cellular convection. Deitsch && .SHORT TERM... (Through Late Tuesday Afternoon) Issued at 416 AM CDT Mon May 25 2020 Most of the convection across our forecast area has dissipated early this morning, except for a small area of showers/storms shifting northward into parts of southeast MO, just south of FAM. There was a weakening MCS over northeast KS and northwest MO, but this should remain west of our forecast area. Although there may be isolated showers this morning, the CAMS are relatively consistent that the majority of the convection will again occur during the afternoon and evening hours as the atmosphere becomes unstable with a continued moist southerly low level flow. Southwest flow shortwaves will continue to move northeastward through the area, ahead of the upper level trough centered over the northern Plains and initiate convection. An MCV over southeast OK will move northeastward through eastern KS and western MO later today and result in the best coverage of storms across northeast and central MO. A few storms may be severe across northeast and central MO and west central IL this afternoon and early this evening with the primary threat being damaging winds. The storms may also produce locally heavy rainfall as well with above normal values of precipitable water. Although there will be more cloud cover this morning compared to Sunday morning, the high temperatures today will continue to be above normal, especially across east central and southeast MO and southwest IL. The deterministic and ensemble guidance are consistent that a cut-off closed low will develop over northern TX on Tuesday in the base of the upper level trough. Although our area will still get at least scattered afternoon and evening convection on Tuesday, it appears that the better threat for severe storms and excessive rain will shift south-southwest of our forecast area, east of the upper level low and its associated surface low. GKS .LONG TERM... (Tuesday Night through Sunday) Issued at 416 AM CDT Mon May 25 2020 Although mainly afternoon and evening convection will continue on Wednesday, the better coverage of showers/storms should be south of our area, ahead of the slow moving surface/upper low moving eastward through northeast TX. A cold front will move slowly southeastward through our forecast area Thursday and Thursday night as a northern stream upper level trough moving eastward through the northern Plains deepens as it moves into the Great Lakes region. Convection is expected along and south of this cold front with the better threat for showers/storms shifting into southeast MO and southwest IL by Friday. Cooler temperatures are forecast from Friday into the weekend as the upper level flow becomes northwesterly, and a surface ridge builds southward into our area from the Northern plains behind the cold front. It also appears that precipitation will shift south-southeast of our forecast area Friday night with dry and cooler conditions for the weekend. GKS && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1208 PM CDT Mon May 25 2020 Main forecast concern will be thunderstorm timing and coverage this afternoon and evening. Have the highest confidence in storms at COU and UIN, where a TEMPO group for TSRA has been added. In the St. Louis metro area, confidence is a bit lower and thus have stuck with VCTS for now and will amend as confidence grows. Otherwise, convective coverage should diminish after the sun sets this evening, leaving a mainly dry and VFR overnight period. Winds will be out of the SE today into tonight around 5-10 knots, but gusts will increase to about 15 knots late Tuesday morning. SPECIFICS FOR KSTL: Main concern will be thunderstorm timing and coverage this afternoon into early this evening. Will continue with VCTS wording for now, but will continue to carefully monitor storm development in southeastern MO and whether that activity can expand and approach the STL terminal by 19-20Z. Otherwise, conditions should be dry and VFR tonight. Additional thunderstorms are possible on Tuesday afternoon. Winds through the period will be out of the SE at 5-10 knots, with higher gusts expected late Tuesday morning into Tuesday afternoon. Deitsch && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service Saint Louis MO 503 AM CDT Mon May 25 2020 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-261015- 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- 503 AM CDT Mon May 25 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. There is a chance of thunderstorms today and tonight, especially during the afternoon and evening. A few of the storms may be severe this afternoon and this evening across northeast and central Missouri and west central Illinois. The primary threat from these storms will be damaging winds, although large hail and isolated tornadoes will also be possible. Some storms may also produce locally heavy rainfall. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. There is a chance of thunderstorms for parts of the area from Tuesday through Friday evening. Major flooding is occurring or forecast along the Illinois River from LaGrange to Valley City. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. Spotters are encouraged to report any severe weather, if observed, to the National Weather Service. GKS
The St Louis radar (KLSX), 83 km away, was scanning. The volume nearest the first event began at 19:44 UTC.
3 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds caused minor damage to several out buildings and tore up a section of fencing.
Thunderstorm winds blew down a large tree onto Highway K, just east of Briscoe.
Thunderstorm winds blew down a large tree onto Highway 79 about two miles east southeast of Louisiana.
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, May 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: 887458, 887459, 887460.