Alert archive / Illinois / Flash Flood Warnings in 2020

Flash Flood Warning 63, NWS St. Louis, MO

August 13, 2020Monroe County, Randolph County, Saint Clair County, Illinois

NWS St. Louis, MO issued this flash flood warning at Aug 13, 2020, 12:17 PM CDT for Monroe County, Randolph County, Saint Clair County, Illinois. It was in force for 6 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: Aug 13, 2020, 12:17 PM CDT (17:17 UTC)
Expired: Aug 13, 2020, 6:15 PM CDT
In force: 6 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

Counties Monroe County, IL, Randolph County, IL, Saint Clair County, IL

The radar

The St Louis radar (KLSX), 87 km from the middle of the area, began a volume at 17:18 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

Time	Report	Where	Remark
Aug 13, 1:55 PM CDT	HEAVY RAIN 4	1 Ene Red Bud, IL	STORM TOTAL, CELL LASTED OVER LOCATION FOR 3 HOURS.
Aug 13, 2:00 PM CDT	FLASH FLOOD	Ruma, IL	ROUTE 3 WAS CLOSED FOR A SHORT TIME IN RUMA DUE TO FLASH FLOODING.
Aug 13, 2:20 PM CDT	FLASH FLOOD	Ruma, IL	REPORT VIA FACEBOOK OF A LOW-CROSSING ROADWAY UNDERWATER. DEPTH IS NOT ESTIMATED.
Aug 13, 2:42 PM CDT	HEAVY RAIN 2.69	2 S Red Bud, IL
Aug 13, 2:48 PM CDT	HEAVY RAIN 2.13	2 Ssw Eden, 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 12:00Z, 5.3 hours before the alert went out and 257 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: 285 J/kg
Mixed-layer CIN: -225 J/kg
Mixed-layer LCL: 984 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 13 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

683 
WGUS53 KLSX 131717
FFWLSX
ILC133-157-163-132315-
/O.NEW.KLSX.FF.W.0063.200813T1717Z-200813T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
1217 PM CDT Thu Aug 13 2020

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southern Monroe County in southwestern Illinois...
  Randolph County in southwestern Illinois...
  Southeastern St. Clair County in southwestern Illinois...

* Until 615 PM CDT.

* At 1216 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 1 to 2 inches of rain have 
  fallen between 11 AM and 1215 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...
  Sparta, Red Bud, New Athens, Marissa, Coulterville, Tilden,
  Evansville, Baldwin, New Design, Eden, Preston, Blair, Prairie Du
  Rocher, Prairie, Lenzburg, Hecker, Ellis Grove, Ruma, Houston and
  Maeystown.

Additional rainfall amounts of 1 to 3 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3800 9004 3801 9006 3802 9010 3804 9013
      3806 9013 3807 9016 3807 9017 3809 9021
      3816 9028 3819 9033 3831 9004 3831 8970
      3822 8970 3822 8959 3805 8959

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

$$

TES

2 follow-up statements

241 
WGUS73 KLSX 131943
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
243 PM CDT Thu Aug 13 2020

ILC133-163-131952-
/O.CAN.KLSX.FF.W.0063.000000T0000Z-200813T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monroe IL-St. Clair IL-
243 PM CDT Thu Aug 13 2020

...THE FLASH FLOOD WARNING FOR SOUTHERN MONROE AND SOUTHEASTERN ST.
CLAIR COUNTIES IS CANCELLED...

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

LAT...LON 3801 8999 3813 9004 3822 9003 3822 8959
      3805 8959

$$

ILC157-132315-
/O.CON.KLSX.FF.W.0063.000000T0000Z-200813T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Randolph IL-
243 PM CDT Thu Aug 13 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM CDT
THURSDAY FOR NORTHEASTERN RANDOLPH COUNTY...

At 242 PM CDT, law enforcement reported thunderstorms producing 
heavy rain in northern Randolph County. Up to 6 inches of rainfall 
have been estimated to have fallen. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported road closures, including Route 3 
         in Ruma.

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...
Sparta, Red Bud, Coulterville, Tilden, Evansville, Baldwin, Eden,
Preston, Blair, Prairie, Ruma, Houston, Walsh and Roots.

Additional rainfall amounts of an inch are possible in the warned 
area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3801 8999 3813 9004 3822 9003 3822 8959
      3805 8959

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

TES

239 
WGUS73 KLSX 132307
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
607 PM CDT Thu Aug 13 2020

ILC157-132316-
/O.EXP.KLSX.FF.W.0063.000000T0000Z-200813T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Randolph IL-
607 PM CDT Thu Aug 13 2020

...THE FLASH FLOOD WARNING FOR NORTHEASTERN RANDOLPH COUNTY WILL
EXPIRE AT 615 PM CDT...

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

LAT...LON 3801 8999 3813 9004 3822 9003 3822 8959
      3805 8959

$$

Glass

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 13, 9:49 AM CDT	Flash Flood Watch	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more	9 hr

Nearby

Flash Flood Warnings in Illinois, 2020 Every 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.