Alert archive / Illinois / Flash Flood Warnings in 2018

Flash Flood Warning 20, NWS St. Louis, MO

June 28, 20184 counties in Illinois

NWS St. Louis, MO issued this flash flood warning at Jun 28, 2018, 7:24 PM CDT for 4 counties in Illinois. It was in force for 4 hr. 5 reports 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
Jun 28, 2018, 7:24 PM CDT (00:24 UTC)
Expired
Jun 28, 2018, 11:15 PM CDT
In force
4 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Clinton County, IL, Monroe County, IL, Saint Clair County, IL, Washington County, IL

The radar

The St Louis radar (KLSX), 93 km from the middle of the area, began a volume at 00:26 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
Jun 28, 7:30 PM CDTFLASH FLOODCentreville, ILSPOTTER REPORTED LANES OF SOUTHBOUND INTERSTATE 255 SUBMERGED.
Jun 28, 7:40 PM CDTHEAVY RAIN 2.81 S Mascoutah, ILDELAYED REPORT: RAIN REPORT SUBMITTED ON SOCIAL MEDIA. RAINFALL TOTAL OCCURRED OVER AN APPROXIMATE SPAN OF 2 HOURS.
Jun 28, 7:46 PM CDTFLASH FLOOD2 Se Belleville, ILREPORT VIA SOCIAL MEDIA OF BACKYARDS BEING SUBMERGED.
Jun 28, 9:23 PM CDTFLASH FLOODFreeburg, ILFLASH FLOODING CONTINUES ACROSS MUCH OF SE ST CLAIR COUNTY. SEVERAL ROADS FLOODED IN THAT AREA.
Jun 28, 10:00 PM CDTHEAVY RAIN 3.02Belleville, ILRAINFALL TOTAL FROM 6:00 PM TO APPROXIMATELY 9:30 PM ON 6/28/2018.

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 00:00Z, 0.4 hours before the alert went out and 217 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 00:00Z on 2018-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1599 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2018-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 55 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
1599 J/kg
Mixed-layer CIN
-203 J/kg
Mixed-layer LCL
1432 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

As transmitted.

175 
WGUS53 KLSX 290024
FFWLSX
ILC027-133-163-189-290415-
/O.NEW.KLSX.FF.W.0020.180629T0024Z-180629T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
724 PM CDT THU JUN 28 2018

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southwestern Clinton County in south central Illinois...
  Eastern Monroe County in southwestern Illinois...
  Washington County in south central Illinois...
  St. Clair County in southwestern Illinois...

* Until 1115 PM CDT.

* At 722 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Very high rainfall rates has 
  resulted in rainfall amounts of up to 2 to 3 inches of rain in 
  just over an hour. There have been several reports of street 
  flooding and flash flooding is possible across the warned area.

* Some locations that will experience flooding include...
  Belleville, O'Fallon, East St. Louis, Fairview Heights, Cahokia,
  Swansea, Shiloh, Columbia, Mascoutah, Centreville, Freeburg,
  Caseyville, Washington Park, Dupo, Millstadt, Madison, New Baden,
  Nashville, Scott AFB and Cahokia Parks Airport.

This includes Interstate 64 in Illinois between exits 9 and 27, and
between exits 41 and 50.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3822 8930 3822 8988 3851 9024 3866 9016
      3854 8974 3834 8923

$$

Glass
2 follow-up statements
404 
WGUS73 KLSX 290225
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
925 PM CDT THU JUN 28 2018

ILC027-133-163-189-290415-
/O.CON.KLSX.FF.W.0020.000000T0000Z-180629T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Monroe IL-Washington IL-St. Clair IL-
925 PM CDT THU JUN 28 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM CDT FOR
SOUTHWESTERN CLINTON...EASTERN MONROE...WASHINGTON AND ST. CLAIR
COUNTIES...

At 920 PM CDT, local law enforcement reported continued widespread 
flash flooding due to heavy rain over southeastern portions of St. 
Clair County. The areas with the worst flooding are Freeburg and 
Mascoutah. Some flooded areas in Washington County have already 
began to recede. 

Some locations that will experience flooding include...
Belleville, O'Fallon, East St. Louis, Fairview Heights, Cahokia,
Swansea, Shiloh, Columbia, Mascoutah, Centreville, Freeburg,
Caseyville, Washington Park, Dupo, Millstadt, Madison, New Baden,
Nashville, Scott AFB and Cahokia Parks Airport.

This includes Interstate 64 in Illinois between exits 9 and 27, and
between exits 41 and 50.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3822 8930 3822 8988 3851 9024 3866 9016
      3854 8974 3834 8923

$$

Tilly
423 
WGUS73 KLSX 290414
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1114 PM CDT THU JUN 28 2018

ILC027-133-163-189-290423-
/O.EXP.KLSX.FF.W.0020.000000T0000Z-180629T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Monroe IL-Washington IL-St. Clair IL-
1114 PM CDT THU JUN 28 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN CLINTON...EASTERN
MONROE...WASHINGTON AND ST. CLAIR COUNTIES WILL EXPIRE AT 1115 PM
CDT...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3822 8930 3822 8988 3851 9024 3866 9016
      3854 8974 3834 8923

$$

Tilly

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 28, 8:07 PM CDTFlash Flood WarningLSXMonroe, Randolph6 hr

Nearby

Flash Flood Warnings in Illinois, 2018Every flash flood warning in 2018

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.