Alert archive / Illinois / Flash Flood Warnings in 2026

Flash Flood Warning 13, NWS St. Louis, MO

April 27, 2026Macoupin County, Illinois

NWS St. Louis, MO issued this flash flood warning at Apr 27, 2026, 6:47 PM CDT for Macoupin County, Illinois. It was in force for 5 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Apr 27, 2026, 6:47 PM CDT (23:47 UTC)
Expired
Apr 27, 2026, 11:45 PM CDT
In force
5 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

County Macoupin County, IL

The radar

The St Louis radar (KLSX), 90 km from the middle of the area, began a volume at 23:49 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.

What was reported inside it

TimeReportWhereRemark
Apr 27, 11:00 PM CDTRAIN 4.4Staunton, ILVia social media--daily total.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.8 hours before the alert went out and 152 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2026-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2026-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1053 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
306 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

675 
WGUS53 KLSX 272347
FFWLSX
ILC117-280445-
/O.NEW.KLSX.FF.W.0013.260427T2347Z-260428T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
647 PM CDT Mon Apr 27 2026

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Macoupin County in southwestern Illinois...

* Until 1145 PM CDT.

* At 647 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Between 2 and 3 inches of rain
  have fallen. Additional rainfall amounts of 1 to 3 inches are
  possible in the warned area. Flash flooding is ongoing or expected
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flash flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other poor
           drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Carlinville, Staunton, Virden, Gillespie, Brighton, Girard, Mount
  Olive, Bunker Hill, Benld, Palmyra, Shipman, Wilsonville,
  Sawyerville, Mount Clare, East Gillespie, Eagarville, Piasa,
  Medora, Nilwood and White City.

This includes the following State Parks...
Beaver Dam State Park.

This includes Interstate 55 in Illinois between exits 41 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3900 8970 3900 9015 3952 9015 3952 8970

FLASH FLOOD...RADAR INDICATED

$$

Carney
2 follow-up statements
139 
WGUS73 KLSX 280228
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
928 PM CDT Mon Apr 27 2026

ILC117-280445-
/O.CON.KLSX.FF.W.0013.000000T0000Z-260428T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Macoupin IL-
928 PM CDT Mon Apr 27 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT THIS
EVENING FOR MACOUPIN COUNTY...

At 928 PM CDT, Doppler radar indicated that the heavy rain has ended,
however between 3 and 5 inches of rain have fallen in the warning
area. Flash flooding continues to be a threat.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Carlinville, Staunton, Virden, Gillespie, Brighton, Girard, Mount
  Olive, Bunker Hill, Benld, Palmyra, Shipman, Wilsonville,
  Sawyerville, Mount Clare, East Gillespie, Eagarville, Piasa,
  Medora, Nilwood and White City.

This includes the following State Parks...
Beaver Dam State Park.

This includes Interstate 55 in Illinois between exits 41 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3900 8970 3900 9015 3952 9015 3952 8970

FLASH FLOOD...RADAR INDICATED

$$

Carney
787 
WGUS73 KLSX 280443
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1143 PM CDT Mon Apr 27 2026

ILC117-280453-
/O.EXP.KLSX.FF.W.0013.000000T0000Z-260428T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Macoupin IL-
1143 PM CDT Mon Apr 27 2026

...FLASH FLOOD WARNING AT 1145 PM CDT THIS EVENING FOR MACOUPIN
COUNTY HAS BEEN REPLACED WITH A FLOOD WARNING...

&&

LAT...LON 3900 8970 3900 9015 3952 9015 3952 8970

$$

Pfahler

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 27, 6:32 AM CDTSevere Thunderstorm WarningLSXClinton, Washington43 min
Apr 27, 7:03 AM CDTSevere Thunderstorm WarningLSXClinton, Marion, Washington57 min
Apr 27, 7:59 AM CDTSevere Thunderstorm WarningLSXGreene, Macoupin, Montgomery33 min
Apr 27, 8:10 AM CDTSevere Thunderstorm Warning Considerable damage threatLSXAdams, Calhoun, Pike65 min
Apr 27, 8:24 AM CDTTornado WarningLSXCalhoun, Pike51 min
Apr 27, 8:57 AM CDTSevere Thunderstorm Warning Considerable damage threatLSXGreene, Pike48 min
Apr 27, 9:03 AM CDTTornado WarningLSXGreene, Pike42 min
Apr 27, 9:44 AM CDTSevere Thunderstorm WarningLSXGreene, Macoupin61 min
Apr 27, 10:29 AM CDTSevere Thunderstorm WarningLSXMacoupin, Montgomery61 min
Apr 27, 10:52 AM CDTSevere Thunderstorm WarningLSXMacoupin, Montgomery42 min
Apr 27, 11:18 AM CDTFlood WatchLSXBond, Calhoun, Clinton, Fayette, Greene, Jersey and 7 more10 hr
Apr 27, 12:09 PM CDTAreal Flood AdvisoryLSXCalhoun3 hr
Apr 27, 12:27 PM CDTTornado WarningLSXMadison, Saint Clair48 min
Apr 27, 1:07 PM CDTFlash Flood WarningLSXFayette, Montgomery7 hr
Apr 27, 1:13 PM CDTTornado WarningLSXMadison47 min
Apr 27, 1:49 PM CDTTornado WarningLSXBond, Madison14 min
Apr 27, 1:55 PM CDTSevere Thunderstorm WarningLSXMadison, Saint Clair45 min
Apr 27, 2:01 PM CDTTornado WarningLSXMadison, Saint Clair27 min
Apr 27, 2:30 PM CDTSevere Thunderstorm WarningLSXBond, Clinton, Madison27 min
Apr 27, 3:05 PM CDTRiver Flood WarningLSXJackson, Randolph8 days
Apr 27, 3:13 PM CDTRiver Flood WarningLSXPike, Scott9 days
Apr 27, 3:14 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene, Jersey, Madison46 min
Apr 27, 3:16 PM CDTRiver Flood WarningLSXFayette4 days
Apr 27, 3:19 PM CDTTornado WarningLSXCalhoun, Jersey, Madison41 min
Apr 27, 3:46 PM CDTSevere Thunderstorm WarningLSXAdams, Pike44 min
Apr 27, 3:52 PM CDTSevere Thunderstorm WarningLSXJersey, Macoupin, Madison38 min
Apr 27, 4:20 PM CDTSevere Thunderstorm WarningLSXAdams, Brown, Pike55 min
Apr 27, 4:34 PM CDTTornado WarningLSXAdams, Brown29 min
Apr 27, 4:46 PM CDTTornado WarningLSXCalhoun, Pike44 min
Apr 27, 4:52 PM CDTFlash Flood WarningLSXAdams, Pike4 hr
Apr 27, 5:20 PM CDTFlash Flood WarningLSXBrown, Pike3 hr
Apr 27, 5:21 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene, Pike39 min
Apr 27, 5:27 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene33 min
Apr 27, 5:32 PM CDTFlash Flood WarningLSXJersey5 hr
Apr 27, 5:32 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene, Jersey, Macoupin43 min
Apr 27, 5:47 PM CDTSevere Thunderstorm WarningLSXCalhoun, Greene, Jersey58 min
Apr 27, 5:50 PM CDTSevere Thunderstorm WarningLSXGreene, Jersey, Macoupin40 min
Apr 27, 5:59 PM CDTSevere Thunderstorm WarningLSXCalhoun, Jersey46 min
Apr 27, 6:01 PM CDTTornado WarningLSXJersey, Macoupin44 min
Apr 27, 6:09 PM CDTSevere Thunderstorm WarningLSXGreene, Macoupin21 min
Apr 27, 6:28 PM CDTSevere Thunderstorm WarningLSXBond, Calhoun, Fayette, Jersey, Macoupin, Madison and 1 more47 min
Apr 27, 6:41 PM CDTTornado WarningLSXCalhoun, Jersey, Madison32 min

Nearby

Flash Flood Warnings in Illinois, 2026Every flash flood warning in 2026

Sources

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