Alert archive / Illinois / Flash Flood Warnings in 2009

Flash Flood Warning 72, NWS St. Louis, MO

September 20, 2009Greene County, Macoupin County, Illinois

NWS St. Louis, MO issued this flash flood warning at Sep 20, 2009, 11:06 AM CDT for Greene County, Macoupin County, Illinois. It was in force for 4 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 20, 2009, 11:06 AM CDT (16:06 UTC)
Expired
Sep 20, 2009, 3:00 PM CDT
In force
4 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Greene County, IL, Macoupin County, IL

The radar

The St Louis radar (KLSX), 80 km from the middle of the area, began a volume at 16:06 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, 4.1 hours before the alert went out and 166 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 2009-09-20Temperature 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 12:00Z on 2009-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.1939Sfc1 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
1235 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KLSX 201606
FFWLSX
ILC061-117-202000-
/O.NEW.KLSX.FF.W.0072.090920T1606Z-090920T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1106 AM CDT SUN SEP 20 2009

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  GREENE COUNTY IN SOUTHWEST ILLINOIS...
  NORTHWESTERN MACOUPIN COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 300 PM CDT

* AT 1102 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE     
  WARNED AREA. LOCAL LAW ENFORCEMENT REPORTED FLOODING OCCURRING    
  ACROSS THE WARNED AREA. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...WHITE
  HALL...ATHENSVILLE...CARROLLTON...GREENFIELD...OLD KANE...PALMYRA
  AND ROODHOUSE.

HIGHWAY 67 WAS CLOSED DUE TO HIGH WATER JUST NORTH OF CARROLLTON. 
NUMEROUS OTHER LOCATIONS WERE REPORTED TO HAVE WATER FLOWING OVER 
ROADWAYS ACROSS THE WARNED AREA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO ARE POSSIBLE IN THE WARNED 
AREA.

&&

LAT...LON 3953 8993 3926 9002 3926 9019 3923 9021
      3923 9031 3918 9032 3918 9056 3953 9054

$$

TILLY
1 follow-up statement
000 
WGUS73 KLSX 201958
FFSLSX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
258 PM CDT SUN SEP 20 2009

ILC061-117-202013-
/O.EXP.KLSX.FF.W.0072.000000T0000Z-090920T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GREENE IL-MACOUPIN IL-
258 PM CDT SUN SEP 20 2009

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR NORTHWESTERN
MACOUPIN AND GREENE COUNTIES WILL BE ALLOWED TO EXPIRE AT 300 PM
CDT...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA HAVE RECEDED OR WERE BEGINNING TO
RECEDE...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN OBSERVED...
PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 3953 8993 3926 9002 3926 9019 3923 9021
      3923 9031 3918 9032 3918 9056 3953 9054

$$

TILLY

Nearby

Flash Flood Warnings in Illinois, 2009Every flash flood warning in 2009

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.