Alert archive / Illinois / Flash Flood Warnings in 2007

Flash Flood Warning 21, NWS Chicago, IL

July 18, 2007LaSalle County, Illinois

NWS Chicago, IL issued this flash flood warning at Jul 18, 2007, 4:22 AM CDT for LaSalle County, Illinois. It was in force for 6 hr. 3 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 18, 2007, 4:22 AM CDT (09:22 UTC)
Expired
Jul 18, 2007, 10:15 AM CDT
In force
6 hr
Issued by
NWS Chicago, IL
Area
Whole counties

County LaSalle County, IL

The radar

The Chicago radar (KLOT), 73 km from the middle of the area, began a volume at 09:22 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
Jul 18, 7:00 AM CDTHEAVY RAIN 3.05Peru, IL
Jul 18, 7:00 AM CDTHEAVY RAIN 3.181 N Mendota, IL
Jul 18, 8:30 AM CDTHEAVY RAIN 2.551 Ese Streator, ILPRECIPITATION RECORDED SINCE MIDNIGHT. DRY CREEK BED HAS RISEN TO 16 INCHES OF FLOWING WATER. COCORAH OBSERVER.

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, 9.4 hours before the alert went out and 135 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 2007-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 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 2007-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 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
46 J/kg
Mixed-layer CIN
-310 J/kg
Mixed-layer LCL
1165 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
119 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 KLOT 180923
FFWLOT
ILC099-181515-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
422 AM CDT WED JUL 18 2007

THE NATIONAL WEATHER SERVICE IN ROMEOVILLE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN LA SALLE COUNTY IN NORTH CENTRAL ILLINOIS...

* UNTIL 1015 AM CDT...

* AT 414 AM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED 
THUNDERSTORMS PRODUCING HEAVY RAIN OVER WESTERN LA SALLE COUNTY.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
MENDOTA...TROY GROVE...LA SALLE AND UTICA.

DOPPLER RADAR AND RAINFALL REPORTS SHOW THAT ONE AND A HALF TO TWO 
INCHES OF RAIN FELL ACROSS WESTERN LA SALLE COUNTY EARLIER THIS 
MORNING.  ANOTHER BAND OF THUNDERSTORMS IN WESTERN LA SALLE COUNTY 
WILL PRODUCE ANOTHER INCH TO 3 INCHES OF RAINFALL.

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.

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. FIND AN ALTERNATE ROUTE.

LAT...LON 4162 8916 4111 8917 4112 8883 4156 8886

$$

HALBACH
3 follow-up statements
000 
WGUS73 KLOT 181209
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
705 AM CDT WED JUL 18 2007

ILC099-181515-
LA SALLE IL-
705 AM CDT WED JUL 18 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 AM CDT FOR
WESTERN LA SALLE COUNTY...

AT 659 AM CDT...RUNOFF CONTINUES FROM HEAVY RAINFALL OVERNIGHT. 
RADAR ESTIMATED THAT BETWEEN 2 AND 4 INCHES OF RAIN FELL OVER 
PORTIONS OF WESTERN LASALLE COUNTY MOSTLY ALONG AND WEST OF A LINE 
FROM MENDOTA TO LEONORE.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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. MOVE TO HIGHER GROUND.

LAT...LON 4162 8916 4111 8917 4112 8883 4156 8886

$$

WDM
000 
WGUS73 KLOT 181409
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
903 AM CDT WED JUL 18 2007

ILC099-181515-
LA SALLE IL-
903 AM CDT WED JUL 18 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 AM CDT FOR
WESTERN LA SALLE COUNTY...

AT 903 AM CDT...RUNOFF CONTINUES FROM HEAVY RAINFALL OVERNIGHT. 
RUNOFF WILL LIKELY CONTINUE FOR AT LEAST ANOTHER HOUR.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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. MOVE TO HIGHER GROUND.

LAT...LON 4162 8916 4111 8917 4112 8883 4156 8886

$$

WDM
000 
WGUS73 KLOT 181513
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 AM CDT WED JUL 18 2007

ILC099-181520-
LA SALLE IL-
1010 AM CDT WED JUL 18 2007

...THE FLASH FLOOD WARNING WILL EXPIRE AT 1015 AM CDT FOR WESTERN
LA SALLE COUNTY. RAINFALL HAS ENDED OVER THE COUNTY AND NO 
ADDITIONAL FLOODING HAS BEEN REPORTED.

ADDITIONAL THUNDERSTORMS THAT MAY PRODUCE HEAVY RAINFALL AND 
FLOODING ARE POSSIBLE LATE THIS AFTERNOON AND TONIGHT.

LAT...LON 4162 8916 4111 8917 4112 8883 4156 8886

$$

WDM

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 18, 12:13 AM CDTSevere Thunderstorm WarningLOTLee, Ogle62 min
Jul 18, 12:49 AM CDTFlash Flood WarningLOTLee6 hr
Jul 18, 3:24 AM CDTSevere Thunderstorm WarningLOTFord, Livingston36 min
Jul 18, 3:31 AM CDTSevere Thunderstorm WarningLOTIroquois44 min
Jul 18, 7:20 AM CDTFlash Flood WarningLOTLivingston6 hr

Nearby

Flash Flood Warnings in Illinois, 2007Every flash flood warning in 2007

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.