Convection developed in south-central Illinois during the very early hours of July 17th. Although flash flooding was the primary concern overnight, one thunderstorm was able to produce wind damage in portions of Macoupin County as it passed.
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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.
Convection developed in south-central Illinois during the very early hours of July 17th. Although flash flooding was the primary concern overnight, one thunderstorm was able to produce wind damage in portions of Macoupin County as it passed.
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 16, 10:00 PM CST, 3 hours 26 minutes earlier. Its key messages:
Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1100 PM CDT Wed Jul 16 2025 .KEY MESSAGES... - A daily chance for showers and thunderstorms continues through this weekend. - A prolonged streak of heat index values >100 degrees is forecast to begin as early as Saturday. && .SHORT TERM... (Through Late Thursday Night) Issued at 241 PM CDT Wed Jul 16 2025 Recent surface observations show a cold front stretching from the Great Lakes southwest through Iowa, northwest Missouri, and Kansas. This feature will sink south tonight into northeast Missouri and west central Illinois, an environment characterized by 4000 J/kg of SBCAPE and 10 to 20 kts of effective shear. The front moving into this high instability air will cause isolated to scattered convective development along it, but low shear will keep activity mostly disorganized. PWATs above the 90th percentile of climatology, landing near 2", will ensure that thunderstorms will be moisture- heavy. Because of this, primary hazards in any thunderstorms that become strong to severe will be gusty to damaging winds. Flash flooding will be a greater concern tonight than the aforementioned wind threat. Overnight, the coverage of thunderstorms is expected to increase under the influence of a weak (20 - 25 kt) low-level jet. Although they'll be weaker due to lessening instability, this will actually make them more conducive for producing efficient heavy rainfall. Cores in this lesser CAPE environment will be less likely to rocket upward and immediately drop their load and die, giving them a higher potential at dropping heavy rain consistently over their lifespan. Deep warm cloud layers of >6 km along with the uncharacteristically high PWATs support efficient rainfall in these cores as well, and weak (15 - 30 kt) mid to upper level shear supports slow moving convection. Although back- building won't be a concern, there will still be the potential for training tonight, which increases the risk for flash flooding in northeast Missouri and west-central Illinois. The HREF LPMM echoes this well with it consistently showing a swath of 3 - 5" of 24 hour rainfall ending Thursday evening. Although the amount and location should not be taken as gospel, it is a good indicator that the threat for flash flooding in these areas is a realistic one. The cold front is forecast to stall in the southern half of the CWA tomorrow. A mid-level shortwave interacting with the front will encourage thunderstorm development during the afternoon in an environment similar to the one discussed in the paragraph above. Training thunderstorms are expected in the vicinity of I-44 (MO)/I- 64 (IL) and south, though this may shift north depending on where exactly the front settles. With weak mid-level shear, deep warm cloud layers, and high PWATs still in place, flash flooding will again be a threat. Portions of southeast Missouri have also seen plenty of rainfall over the past few weeks, making them more susceptible to flash flooding than other locations. Tomorrow, the front will provide heat relief those behind it. Areas north of I-70 will struggle to hit 85 degrees with similar heat index values. Ahead of the front, however, the heat will be similar to that of today. Jaja && .LONG TERM... (Friday through Next Wednesday) Issued at 241 PM CDT Wed Jul 16 2025 The cold front turned quasi-stationary front will meander around the forecast area from Friday through Monday. Multiple shortwaves interacting with it and ample instability each day will keep the potential for showers and thunderstorms around over the same period to varying degrees. By Saturday, ridging to our south will push the front over our northern CWA, lending most of the area over to a heat concern rather than severe weather/flash flooding. This heat concern will last through at least the middle of next week as temperatures in the 90s and dewpoints in the 70s combine to create heat index values of 100 to 105+ degree each day. A heat headline will need to be issued down the line, despite model variation in the strength and intensity of the ridge. The more impactful uncertainty is how the front and passing shortwaves affect the heat forecast in northeast Missouri and west-central Illinois. Possible increased cloud cover and rain would leave these locations cooler than the rest, perhaps not reaching Advisory criteria. This will need to be assessed in future forecast issuances. For now, confidence is high in a long duration hot streak outside of these areas. Jaja && .AVIATION... (For the 06z TAFs through 06z Thursday Night) Issued at 1043 PM CDT Wed Jul 16 2025 A cold front will slowly sink southward overnight into Thursday, bringing a long duration of off/on thunderstorm potential as it begins to stall across the region. Thunderstorms over the northwestern quadrant of Missouri are expected to eventually work eastward into central Missouri, potentially impacting KCOU near the start of the period. As instability wanes overnight, coverage is expected to decrease, but not entirely diminish. By Thursday late morning/early afternoon, thunderstorm potential increases once again along and south of the boundary, focusing the best potential over central Missouri and metro terminals. Thunderstorms will be capable of very heavy rain, visibility restrictions and gusty winds. These scenarios are difficult to provide details, as specific timing and impacts can change quickly due to competing outflow from thunderstorms in a weak flow environment. Therefore, the forecast is best conveyed with general diurnal trends, which support scattered to numerous thunderstorms during the daylight hours and lull during the nighttime periods. In addition to thunderstorm potential, MVFR ceilings are possible in the early morning periods as the front waffles north/south through at least early Friday. Maples && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && WFO LSX
Hazardous Weather Outlook National Weather Service St Louis MO 237 PM CDT Wed Jul 16 2025 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-171945- 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-Knox MO- Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO- Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway 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- 237 PM CDT Wed Jul 16 2025 This Hazardous Weather Outlook is for portions of eastern and central Missouri as well as west central and southwest Illinois. .DAY ONE...Tonight. There is a chance of thunderstorms tonight. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. There is a chance of thunderstorms each day from Thursday through Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. Jaja
Preliminary Local Storm Report
National Weather Service St Louis MO
916 PM CDT Wed Jul 16 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0545 PM Tstm Wnd Dmg Saint Elmo 39.03N 88.85W
07/16/2025 Fayette IL Emergency Mngr
Limbs up to 4 inches in diameter snapped in
St. Elmo. Time estimated from radar.
&&
AEPreliminary Local Storm Report
National Weather Service St Louis MO
934 PM CDT Wed Jul 16 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0528 PM Tstm Wnd Dmg 5 NE Ramsey 39.19N 89.03W
07/16/2025 Fayette IL Emergency Mngr
Tree down at the Ramsey substation. Time
estimated from radar.
&&
AEThe St Louis radar (KLSX), 81 km away, was scanning. The volume nearest the first event began at 07:26 UTC.
2 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds downed a tree on Valley Road.
Thunderstorm winds downed a tree along Route 66.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2025Every state in 2025This day in weather historyWarnings in Illinois, July 2025
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: 1273597, 1273599.