Alert archive / Illinois / Flash Flood Warnings in 2018

Flash Flood Warning 38, NWS St. Louis, MO

September 7, 20184 counties in Illinois

NWS St. Louis, MO issued this flash flood warning at Sep 7, 2018, 5:31 PM CDT for 4 counties in Illinois. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 7, 2018, 5:31 PM CDT (22:31 UTC)
Expired
Sep 7, 2018, 11:30 PM 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, Macoupin County, IL, Montgomery County, IL

The radar

The Lincoln radar (KILX), 106 km from the middle of the area, began a volume at 22:32 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.5 hours before the alert went out and 126 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 2018-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 21 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 12:00Z on 2018-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 147 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
21 J/kg
Mixed-layer CIN
-103 J/kg
Mixed-layer LCL
672 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
147 m²/s²
0-3 km storm-relative helicity
165 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

114 
WGUS53 KLSX 072231
FFWLSX
ILC005-051-117-135-080430-
/O.NEW.KLSX.FF.W.0038.180907T2231Z-180908T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
531 PM CDT FRI SEP 7 2018

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  North central Bond County in south central Illinois...
  Northwestern Fayette County in south central Illinois...
  Southeastern Macoupin County in southwestern Illinois...
  Montgomery County in south central Illinois...

* Until 1130 PM CDT Friday.

* At 529 PM CDT, Doppler radar indicated heavy rain across the 
  warned area. Up to three inches of rain have already fallen from 
  Mount Olive to Nokomis during the past three hours. Flash flooding 
  is expected to begin shortly.

* Some locations that will experience flooding include...
  Litchfield, Hillsboro, Nokomis, Mount Olive, Raymond, Witt, Taylor
  Springs, Coffeen, Schram City, Sorento, Van Burensburg, Irving,
  Panama, Fillmore, Coalton, Harvel, Donnellson, Butler, Ohlman and
  Bingham.

This includes Interstate 55 in Illinois between exits 52 and 60.
 
This also includes  Ramsey Lake State Park and Lake Lou Yaeger.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3903 8928 3900 8965 3900 8974 3918 8977
      3942 8955 3942 8953 3935 8953 3935 8914
      3922 8914 3922 8910 3920 8910

$$

GKS
1 follow-up statement
921 
WGUS73 KLSX 080429
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1129 PM CDT FRI SEP 7 2018

ILC005-051-117-135-080435-
/O.EXP.KLSX.FF.W.0038.000000T0000Z-180908T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bond IL-Fayette IL-Macoupin IL-Montgomery IL-
1129 PM CDT FRI SEP 7 2018

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL BOND...NORTHWESTERN
FAYETTE...SOUTHEASTERN MACOUPIN AND MONTGOMERY COUNTIES WILL EXPIRE
AT 1130 PM CDT...

The heavy rain that resulted in the warning earlier this evening has 
ended. No additional flooding has been observed. Additional flooding 
is not expected to pose an immediate threat at this time, but more 
heavy rainfall could impact the area overnight. Please continue to 
heed any remaining road closures.

LAT...LON 3903 8928 3900 8965 3900 8974 3918 8977
      3942 8955 3942 8953 3935 8953 3935 8914
      3922 8914 3922 8910 3920 8910

$$

Maples

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 6, 8:26 PM CDTRiver Flood WarningLSXBrown60 hr
Sep 6, 10:20 PM CDTRiver Flood WarningLSXAdams6 days
Sep 7, 10:12 AM CDTAreal Flood AdvisoryLSXAdams3 hr
Sep 7, 10:33 AM CDTFlash Flood WarningLSXAdams6 hr
Sep 7, 4:31 PM CDTAreal Flood WarningLSXAdams18 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.