Alert archive / Illinois / Severe Thunderstorm Warnings in 2024

Severe Thunderstorm Warning 260, NWS St. Louis, MO

May 26, 20244 counties in Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at May 26, 2024, 6:16 PM CDT for 4 counties in Illinois. It was in force for 59 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 26, 2024, 6:16 PM CDT (23:16 UTC)
Expired: May 26, 2024, 7:15 PM CDT
In force: 59 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Bond County, IL, Clinton County, IL, Fayette County, IL, Madison County, IL

The radar

The St Louis radar (KLSX), 108 km from the middle of the area, began a volume at 23:17 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 26, 4:01 PM CDT	Tornado Watch PDS	SPC	7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.3 hours before the alert went out and 164 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 394 J/kg
Mixed-layer CIN: -126 J/kg
Mixed-layer LCL: 637 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 251 m²/s²
0-3 km storm-relative helicity: 239 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.6

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at May 26, 6:09 PM CDT, 7 minutes earlier. Its key messages:

-Significant severe thunderstorms are likely through this evening, along and south of I-70. The main threats are very large hail (2"+), damaging winds (70-80+ mph), and strong tornadoes (EF2 or higher). -Locally heavy rainfall, up to 2-5 inches, is possible with this round of storms. -Dry and mild weather expected through the work week with temperatures near normal.

Area forecast discussion, May 26, 6:09 PM CDT, 7 minutes before

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
609 PM CDT Sun May 26 2024

.KEY MESSAGES...

-Significant severe thunderstorms are likely through this evening,
along and south of I-70. The main threats are very large hail (2"+),
damaging winds (70-80+ mph), and strong tornadoes (EF2 or higher).

-Locally heavy rainfall, up to 2-5 inches, is possible with this
round of storms.

-Dry and mild weather expected through the work week with
 temperatures near normal.

&&

.SHORT TERM...  (Through Late Monday Night)
Issued at 316 PM CDT Sun May 26 2024

Latest visible satellite and radar imagery indicates that a cu
field is developing between I-70 and I-44, as well as scattered
storms as of 20z. In the meantime, strong heating is occurring in
this area with steep LR (8-8.5C/km), MU CAPEs 2000-3000 J/kg, as
well as decent deep layer shear (50-60kts). So thunderstorms will
continue to develop in this area within the strongly sheared
environment. Supercells will be the dominant convective mode then
transition to a more linear structure as the activity exits the
forecast area later this evening. There is a risk for all severe
hazards including very large hail (2"+), damaging winds (70-80+
mph) and strong tornadoes (EF2 or higher), especially along and
south of I-70.

Otherwise, there is still the possibility of locally heavy rainfall
as the storms move through. With west-east shear parallel to the
outflow boundary, could see training storms through this evening.
The latest HREF probability matched mean indicates the potential for
rainfall up to 2" over a 3 hour period. Areas that have already seen
modest rainfall in the past two days will be at higher risk for
flash flooding. So the Flood Watch remains in effect until 06z
Monday.

Surface ridge will build in behind the cold front late tonight with
dry and pleasant weather returning on Monday. Lows tonight will be
in the mid 50s to low 60s. In the meantime, a secondary shortwave
will rotate around the system and sink southeast through the
forecast area during the day on Monday. Will see increasing cu
field, but the best chances for showers will be just north of the
forecast area. Highs will be in the upper 70s to mid 80s.

Byrd
&&

.LONG TERM...  (Tuesday through Next Sunday)
Issued at 316 PM CDT Sun May 26 2024

Upper level ridge will build over the western CONUS while
troughing lingers over the eastern half. Therefore the forecast
area will be in northwest flow aloft with temperatures a bit below
normal through the end of the work week. Otherwise, the pattern
begins to change late in the work week with chances of rain
returning by next weekend.

Byrd
&&

.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 606 PM CDT Sun May 26 2024

Cold front has moved through KUIN, KCOU and KJEF with winds from
the northwest. Otherwise, the front is in the process of moving
through the St. Louis metro area, so kept a one hour tempo group
for MVFR ceilings and visibilities with the storms. Then rain will
move out by 02z Monday for metro area with winds veering to the
northwest.

Rest of forecast period will be VFR with northwest winds. Could
see some gusts up to 20 kts Monday afternoon with some scattered
CU as a weak shortwave moves through.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch until 1 AM CDT Monday for Audrain MO-Boone MO-
     Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
     Iron MO-Jefferson MO-Lincoln MO-Madison MO-Moniteau MO-
     Montgomery MO-Osage MO-Pike MO-Reynolds MO-Saint Charles MO-
     Saint Francois MO-Saint Louis City MO-Saint Louis MO-Sainte
     Genevieve MO-Warren MO-Washington MO.

IL...Flood Watch until 1 AM CDT Monday for Bond IL-Calhoun IL-Clinton
     IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-Madison IL-
     Marion IL-Monroe IL-Montgomery IL-Randolph IL-Saint Clair
     IL-Washington IL.

&&

WFO LSX

Hazardous weather outlook, May 26, 4:19 PM CDT, 1 hour 57 minutes before

Hazardous Weather Outlook
National Weather Service St Louis MO
419 PM CDT Sun May 26 2024

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-272130-
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-
419 PM CDT Sun May 26 2024

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 expected through this evening with significant
severe storms possible. Damaging winds up to 80 mph, large hail up to
two inches in diameter, strong tornadoes, and flash flooding are the
primary hazards.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a chance of thunderstorms Friday through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will be needed. Spotters are encouraged to
report any severe weather, if observed, to the National Weather
Service.

Byrd

In the hours before

Local storm report, May 26, 5:58 PM CDT, 18 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
558 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0558 PM     Hail             1 ESE Troy              38.72N 89.87W
05/26/2024  E1.75 Inch       Madison            IL   Trained Spotter

&&

PW

Local storm report, May 26, 6:01 PM CDT, 15 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
601 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0601 PM     Hail             1 WNW Lakeshire         38.55N 90.36W
05/26/2024  E1.00 Inch       St. Louis          MO   Public

&&

AE

Local storm report, May 26, 6:02 PM CDT, 14 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
602 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0602 PM     Hail             1 N Webster Groves      38.59N 90.35W
05/26/2024  E1.00 Inch       St. Louis          MO   Trained Spotter

&&

PW

Local storm report, May 26, 6:04 PM CDT, 12 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
604 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0603 PM     Hail             2 NNW Saint Jacob       38.74N 89.78W
05/26/2024  E1.25 Inch       Madison            IL   Trained Spotter

&&

AE

Local storm report, May 26, 6:06 PM CDT, 10 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
606 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0552 PM     Hail             1 E Kirkwood            38.58N 90.40W
05/26/2024  M1.00 Inch       St. Louis          MO   Trained Spotter

&&

AE

Local storm report, May 26, 6:14 PM CDT, 2 minutes before

Preliminary Local Storm Report
National Weather Service St Louis MO
614 PM CDT Sun May 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0610 PM     Hail             1 SE Cahokia            38.55N 90.16W
05/26/2024  E1.00 Inch       St. Clair          IL   Trained Spotter

&&

PW

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 26, 12:31 AM CDT	Severe Thunderstorm Warning	LSX	Moniteau	29 min
May 26, 12:57 AM CDT	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Moniteau	33 min
May 26, 5:37 AM CDT	Severe Thunderstorm Warning	LSX	Reynolds	38 min
May 26, 5:59 AM CDT	Severe Thunderstorm Warning	LSX	Iron	46 min
May 26, 6:15 AM CDT	Severe Thunderstorm Warning	LSX	Madison, Saint Francois	45 min
May 26, 6:40 AM CDT	Areal Flood Advisory	LSX	Boone, Callaway	3 hr
May 26, 11:50 AM CDT	River Flood Warning	LSX	Perry, Sainte Genevieve	4 days
May 26, 3:17 PM CDT	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Moniteau	43 min
May 26, 3:30 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade, Montgomery, Osage, Warren	45 min
May 26, 3:45 PM CDT	Severe Thunderstorm Warning	LSX	Callaway, Gasconade, Montgomery, Osage	45 min
May 26, 3:46 PM CDT	River Flood Warning	LSX	Reynolds	65 hr
May 26, 4:06 PM CDT	Severe Thunderstorm Warning	LSX	Cole, Osage	39 min
May 26, 4:09 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Franklin, Gasconade, Warren	51 min
May 26, 4:14 PM CDT	Areal Flood Advisory	LSX	Cole, Osage	3 hr
May 26, 4:37 PM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis	38 min
May 26, 4:39 PM CDT	Severe Thunderstorm Warning	LSX	Gasconade, Osage	51 min
May 26, 4:47 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Jefferson, Saint Charles, Saint Louis, Warren	43 min
May 26, 4:58 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Warren	35 min
May 26, 5:01 PM CDT	Areal Flood Advisory	LSX	Saint Charles, Saint Louis	3 hr
May 26, 5:05 PM CDT	Areal Flood Advisory	LSX	Franklin, Gasconade, Montgomery, Saint Charles, Warren	3 hr
May 26, 5:09 PM CDT	Tornado Warning	LSX	Franklin, Jefferson, Saint Louis	51 min
May 26, 5:11 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Saint Charles, Saint Louis, City of Saint Louis	38 min
May 26, 5:27 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Saint Charles, Saint Louis	35 min
May 26, 5:43 PM CDT	Tornado Warning	LSX	Saint Louis, City of Saint Louis	47 min
May 26, 5:48 PM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis	15 min
May 26, 5:49 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Franklin, Jefferson, Washington	41 min
May 26, 6:06 PM CDT	Severe Thunderstorm Warning	LSX	Crawford	39 min
May 26, 6:09 PM CDT	Tornado Warning	LSX	Reynolds	51 min
May 26, 6:14 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Sainte Genevieve, Saint Francois	46 min
May 26, 6:16 PM CDT	Severe Thunderstorm Warning	LSX	Iron, Washington	44 min
May 26, 6:26 PM CDT	Severe Thunderstorm Warning	LSX	Sainte Genevieve	49 min
May 26, 6:30 PM CDT	Areal Flood Advisory	LSX	City of Saint Louis	3 hr
May 26, 6:44 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Iron, Sainte Genevieve, Saint Francois, Washington	46 min
May 26, 6:46 PM CDT	Tornado Warning	LSX	Reynolds	27 min
May 26, 6:51 PM CDT	Tornado Warning	LSX	Iron, Madison, Reynolds	39 min
May 26, 4:45 PM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Greene, Jersey	45 min
May 26, 5:03 PM CDT	Severe Thunderstorm Warning	LSX	Macoupin, Montgomery	42 min
May 26, 5:29 PM CDT	Severe Thunderstorm Warning	LSX	Madison	61 min
May 26, 6:09 PM CDT	Tornado Warning	LSX	Saint Clair	51 min
May 26, 6:34 PM CDT	Areal Flood Advisory	LSX	Madison	3 hr
May 26, 6:38 PM CDT	Tornado Warning	LSX	Clinton, Randolph, Saint Clair, Washington	67 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2024 Every severe thunderstorm warning in 2024

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.