Alert archive / Illinois / Flash Flood Warnings in 2020

Flash Flood Warning 42, NWS St. Louis, MO

July 19, 20204 counties in Illinois

NWS St. Louis, MO issued this flash flood warning at Jul 19, 2020, 9:03 PM CDT for 4 counties in Illinois. It was in force for 6 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
Jul 19, 2020, 9:03 PM CDT (02:03 UTC)
Expired
Jul 20, 2020, 3:00 AM CDT
In force
6 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Bond County, IL, Clinton County, IL, Fayette County, IL, Marion County, IL

The radar

The St Louis radar (KLSX), 121 km from the middle of the area, began a volume at 02:07 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
Jul 19, 10:39 PM CDTHEAVY RAIN 2.7Aviston, IL

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, 2.1 hours before the alert went out and 182 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 2020-07-20Temperature 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 00:00Z on 2020-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
1662 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

806 
WGUS53 KLSX 200203
FFWLSX
ILC005-027-051-121-200800-
/O.NEW.KLSX.FF.W.0042.200720T0203Z-200720T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
903 PM CDT Sun Jul 19 2020

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Clinton County in south central Illinois...
  Southern Bond County in south central Illinois...
  Marion County in south central Illinois...
  Southern Fayette County in south central Illinois...

* Until 300 AM CDT.

* At 901 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 1 to 2 inches of rain have 
  fallen between 7:30 and 9 PM CDT. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that will experience flooding include...
  Centralia, Salem, Vandalia, Greenville, Breese, New Baden, Carlyle,
  Trenton, Aviston, St. Elmo, St. Rose, Sandoval, Germantown, Albers,
  Wamac, Central City, Odin, Beckemeyer, Kinmundy and Pocahontas.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

This also includes Carlyle Lake Recreational Area.
 
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.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3847 8914 3850 8915 3852 8936 3850 8937
      3850 8943 3847 8948 3847 8961 3843 8968
      3848 8971 3865 8971 3866 8959 3884 8960
      3908 8881 3891 8881 3891 8869 3847 8870

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

TES
1 follow-up statement
514 
WGUS73 KLSX 200800
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
300 AM CDT Mon Jul 20 2020

ILC005-027-051-121-200809-
/O.EXP.KLSX.FF.W.0042.000000T0000Z-200720T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Bond IL-Marion IL-Fayette IL-
300 AM CDT Mon Jul 20 2020

...THE FLASH FLOOD WARNING FOR CLINTON...SOUTHERN BOND...MARION AND
SOUTHERN FAYETTE COUNTIES WILL EXPIRE AT 300 AM CDT MONDAY...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3847 8914 3850 8915 3852 8936 3850 8937
      3850 8943 3847 8948 3847 8961 3843 8968
      3848 8971 3865 8971 3866 8959 3884 8960
      3908 8881 3891 8881 3891 8869 3847 8870

$$

Gosselin

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 8:08 PM CDTSevere Thunderstorm WarningLSXMadison, Saint Clair39 min
Jul 19, 8:34 PM CDTFlash Flood WarningLSXMadison, Saint Clair6 hr

Nearby

Flash Flood Warnings in Illinois, 2020Every flash flood warning in 2020

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.