Alert archive / Illinois / Flash Flood Warnings in 2012

Flash Flood Warning 27, NWS St. Louis, MO

September 25, 2012Clinton County, Washington County, Illinois

NWS St. Louis, MO issued this flash flood warning at Sep 25, 2012, 8:59 PM CDT for Clinton County, Washington County, 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 25, 2012, 8:59 PM CDT (01:59 UTC)
Expired
Sep 26, 2012, 3:00 AM CDT
In force
6 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Clinton County, IL, Washington County, IL

The radar

The St Louis radar (KLSX), 120 km from the middle of the area, began a volume at 01:59 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 00:00Z, 2.0 hours before the alert went out and 188 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 2012-09-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1015 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 2012-09-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 145 square meters per square second.19395878Sfc1 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
1015 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
957 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
145 m²/s²
0-3 km storm-relative helicity
222 m²/s²
Significant tornado parameter
0.9
Supercell composite
5.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

904 
WGUS53 KLSX 260159
FFWLSX
ILC027-189-260800-
/O.NEW.KLSX.FF.W.0027.120926T0159Z-120926T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
859 PM CDT TUE SEP 25 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN WASHINGTON COUNTY IN SOUTH CENTRAL ILLINOIS...
  SOUTHERN CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...

* UNTIL 300 AM CDT WEDNESDAY

* AT 856 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE   
  WARNED AREA. AN AUTOMATED RAIN GAUGE ON CROOKED CREEK SOUTHEAST
  OF POSEY IS REPORTING A TOTAL OF 3.5 INCHES.  AN ADDITIONAL 1 TO
  3 INCHES CAN BE EXPECTED THROUGH THE REST OF THE NIGHT.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  BREESE...CARLYLE...BECKEMEYER...GERMANTOWN...IRVINGTON...
  OKAWVILLE...SHATTUC AND WAMAC.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. DO
NOT ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND TO
ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN
WATER BEGINS RISING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3864 8914 3841 8915 3841 8957 3864 8956

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 25, 7:05 PM CDTSevere Thunderstorm WarningLSXCalhoun40 min
Sep 25, 7:29 PM CDTSevere Thunderstorm WarningLSXMarion, Washington46 min
Sep 25, 8:11 PM CDTSevere Thunderstorm WarningLSXBond, Clinton, Madison, Saint Clair34 min
Sep 25, 8:13 PM CDTSevere Thunderstorm WarningLSXMadison, Saint Clair47 min
Sep 25, 8:38 PM CDTSevere Thunderstorm WarningLSXBond, Clinton, Fayette, Marion52 min
Sep 26, 3:01 AM CDTFlash Flood WarningLSXClinton, Marion, Washington6 hr
Sep 26, 9:08 AM CDTAreal Flood WarningLSXClinton, Marion, Washington12 hr

Nearby

Flash Flood Warnings in Illinois, 2012Every flash flood warning in 2012

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.