A west-to-east oriented instability gradient over Missouri resulted in weakening thunderstorms as they entered central Missouri. One dying thunderstorm produced sporadic tree damage in Boone 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.
A west-to-east oriented instability gradient over Missouri resulted in weakening thunderstorms as they entered central Missouri. One dying thunderstorm produced sporadic tree damage in Boone 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 Sep 23, 5:58 PM CST, 1 hour 57 minutes earlier.
Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 658 PM CDT Sat Sep 23 2023 .SHORT TERM... (Through Late Sunday Night) Issued at 248 PM CDT Sat Sep 23 2023 Key Messages: 1.) Thunderstorms are expected to reach central MO late this afternoon. Some storms could be strong to severe in central MO this afternoon/evening. However, the probability of severe weather is low. 2.) Thunderstorm redevelopment is possible on Sunday. However, severe weather is not expected. 3.) Confidence is increasing that above average temps will prevail next week along with largely dry conditions. Thunderstorms developed early this morning to the west of the area on the nose of a low level jet in far western MO. This activity has continued and slowly drifted east through the rest of the morning and into the early afternoon hours, with a Severe Thunderstorm Watch posted to our west in western MO. The recent set of hi-res models continue to promote the idea that the current storms will drift east and dissipate while storms redevelop in the mid to late afternoon hours further west near the KS/MO border. The current forecast grids reflect this thinking with storms slowly becoming more likely in our western zones across central MO as the evening hours approach. Instability drops off considerably today as you go from west to east across MO. MUCAPEs drop from 1000-3000 J/kg in western MO to around 1000 J/kg in central MO and to near zero in eastern MO based on the latest mesoanalysis. This gradient will hold through the evening, resulting in dying storms as they push east. Still, severe storms will be possible in the western zones across central MO this afternoon and evening with large hail and damaging winds being the primary threats. A few showers with embedded thunderstorms will be possible tomorrow morning before surface-based redevelopment occurs tomorrow. Severe storms are not expected tomorrow given the weak shear (~20 kts) and limited instability (500-1000 J/kg). Generally have 20-40 percent chance of precip tomorrow afternoon and evening with this activity. Knutsvig .LONG TERM... (Monday through Next Saturday) Issued at 248 PM CDT Sat Sep 23 2023 The extended forecast looks warm and dry with northwest flow expected due to an upper low to the north over IA/northern IL and moving into the Great Lakes region late in the week. Highs are expected to be in the upper 70s to low 80s with lows around 60. There are a couple of periods with 20 percent chances of precip as the upper low brushes by to the north around mid week. Limited precipitation would be expected if this becomes realized. Knutsvig && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 642 PM CDT Sat Sep 23 2023 Thunderstorms over western Missouri are expected to move east and affect UIN, COU, and JEF between 01-05Z. Any thunderstorms will be capable of producing MVFR, possible IFR ceilings and visibilities in brief heavy rain. The chance for showers and thunderstorms will continue at these sites before waning overnight with another chance for showers and thunderstorms at all of the terminals on Sunday. Winds will remain 10 knots or less through the period. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service St Louis MO Issued by National Weather Service Lincoln IL 110 PM CDT Sat Sep 23 2023 ILZ058>060-064-065-069-070-074-079-095>102-MOZ036-051-052-059>065- 072>075-084-085-099-241815- Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL- Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL- Calhoun IL-Jersey IL-Madison IL-Saint Clair IL-Monroe IL-Pike MO- Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO- Franklin MO-Saint Louis MO-Saint Louis City MO-Jefferson MO- Crawford MO-Washington MO-Saint Francois MO-Sainte Genevieve MO- Iron MO-Madison MO-Reynolds MO- 110 PM CDT Sat Sep 23 2023 This Hazardous Weather Outlook is for south central Illinois, southwest Illinois, west central Illinois, east central Missouri, northeast Missouri and southeast Missouri. .DAY ONE...This afternoon and tonight. There is a chance of thunderstorms this evening into overnight, especially in central and northeastern Missouri. .DAYS TWO THROUGH SEVEN...Sunday through Friday. There is a chance of thunderstorms Sunday into Sunday night across portions of the area. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MOZ018-019-026-027-034-035-041-042-047>050-241815- Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Boone MO- Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO- 110 PM CDT Sat Sep 23 2023 This Hazardous Weather Outlook is for central Missouri and northeast Missouri. .DAY ONE...This afternoon and tonight. Thunderstorms are possible late this afternoon and this evening across parts of central MO. Some storms may be strong to severe with damaging winds and large hail being the primary threats. .DAYS TWO THROUGH SEVEN...Sunday through Friday. There is a chance of thunderstorms Sunday into Sunday night across portions of the area. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. Knutsvig
The St Louis radar (KLSX), 136 km away, was scanning. The volume nearest the first event began at 01:53 UTC.
1 thunderstorm wind. Local standard time, as filed.
Sporadic tree damage was reported in Ashland, including tree that was uprooted. No information on the trees was given.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2023Every state in 2023This day in weather historyWarnings in Missouri, September 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: 1148683.