Alert archive / Illinois / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS St. Louis, MO

August 31, 2021Bond County, Fayette County, Montgomery County, Illinois

NWS St. Louis, MO issued this flash flood warning at Aug 31, 2021, 11:37 PM CDT for Bond County, Fayette County, Montgomery County, 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
Aug 31, 2021, 11:37 PM CDT (04:37 UTC)
Expired
Sep 1, 2021, 5:30 AM CDT
In force
6 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Bond County, IL, Fayette County, IL, Montgomery County, IL

The radar

The Lincoln radar (KILX), 108 km from the middle of the area, began a volume at 04:41 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
Sep 1, 3:00 AM CDTFLASH FLOODIrving, ILFLOODING ON ROUTE 16 IN THE TOWNS OF IRVING AND WITT AND ALSO ON COFFEEN ROAD AND FILLMORE TRAIL.

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, 4.6 hours before the alert went out and 123 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 59 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
59 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
1442 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted.

556 
WGUS53 KLSX 010437
FFWLSX
ILC005-051-135-011030-
/O.NEW.KLSX.FF.W.0041.210901T0437Z-210901T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
1137 PM CDT Tue Aug 31 2021

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Northern Bond County in south central Illinois...
  Northwestern Fayette County in south central Illinois...
  Montgomery County in south central Illinois...

* Until 530 AM CDT.

* At 1137 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 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  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...
  Vandalia, Greenville, Hillsboro, Nokomis, Ramsey, Witt, Taylor 
  Springs, Coffeen, Mulberry Grove, Schram City, Sorento, Van 
  Burensburg, Woburn, Reno, Irving, Shafter, Panama, Fillmore, 
  Coalton and Donnellson.

This includes the following State Parks...
	Ramsey Lake State Park.

This includes the following highways...
	Interstate 70 in Illinois between exits 52 and 63.

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 3935 8955 3935 8915 3922 8914 3921 8902
      3889 8902 3890 8961

FLASH FLOOD...RADAR INDICATED

$$

GKS

Nearby

Flash Flood Warnings in Illinois, 2021Every flash flood warning in 2021

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.