Alert archive / Illinois / Flash Flood Warnings in 2007

Flash Flood Warning 35, NWS Chicago, IL

August 22, 2007Grundy County, Kendall County, LaSalle County, Illinois

NWS Chicago, IL issued this flash flood warning at Aug 22, 2007, 9:50 PM CDT for Grundy County, Kendall County, LaSalle County, Illinois. It took effect at Aug 22, 2007, 9:56 PM CDT. 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 counties it named.

The facts

Issued
Aug 22, 2007, 9:50 PM CDT (02:50 UTC)
In effect from
Aug 22, 2007, 9:56 PM CDT
Expired
Aug 23, 2007, 1:45 AM CDT
In force
4 hr
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Grundy County, IL, Kendall County, IL, LaSalle County, IL

The radar

The Chicago radar (KLOT), 47 km from the middle of the area, began a volume at 02:53 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, 2.8 hours before the alert went out and 140 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 2007-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1568 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2007-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
1568 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
1750 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
195 m²/s²
Significant tornado parameter
0.2
Supercell composite
6.6

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KLOT 230256
FFWLOT
ILC063-093-099-230645-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
950 PM CDT WED AUG 22 2007

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  LA SALLE COUNTY IN NORTH CENTRAL ILLINOIS...
  THIS INCLUDES THE CITIES OF...SERENA...STREATOR...SENECA...
  OTTAWA...MARSEILLES...
  GRUNDY COUNTY IN NORTHEAST ILLINOIS...
  THIS INCLUDES THE CITY OF MORRIS...
  KENDALL COUNTY IN NORTHEAST ILLINOIS...
  THIS INCLUDES THE CITY OF YORKVILLE...

* UNTIL 145 AM CDT

* AT 950 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN OF 1 TO 2 INCHES HAS FALLEN FROM SOUTHERN LASALLE  
  COUNTY EXTENDING INTO NORTHERN GRUNDY COUNTY. SHOWERS AND          
  THUNDERSTORMS WILL CONTINUE TO MOVE ACROSS THESE SAME LOCATIONS    
  THROUGH 11 PM CDT...PRODUCING UP TO 2 INCHES OF ADDITIONAL         
  RAINFALL WHICH IS EXPECTED TO LEAD TO FLASH FLOODING.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO GARDNER...
  TONICA...SHERIDAN...NEWARK...NAPLATE...MAZON...GRAND RIDGE AND COAL
  CITY

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

LAT...LON 4114 8916 4111 8866 4118 8828 4170 8828
      4153 8886

$$

MARSILI
3 follow-up statements
000 
WGUS73 KLOT 230422
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1114 PM CDT WED AUG 22 2007

ILC063-093-099-230645-
GRUNDY IL-KENDALL IL-LA SALLE IL-
1114 PM CDT WED AUG 22 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 AM CDT FOR LA
SALLE...KENDALL AND GRUNDY COUNTIES...

AT 1112 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS CONTINUING ACROSS THE WARNED AREA. RADAR ESTIMATES 
THAT BETWEEN 2 AND 3 INCHES OF RAIN HAS FALLEN FROM SOUTHERN LASALLE 
COUNTY INTO NORTHERN GRUNDY AND FAR SOUTHERN KENDALL COUNTIES SINCE 
8 PM CDT. ADDITIONAL RAINFALL AMOUNTS BETWEEN A HALF INCH AND AN 
INCH ARE POSSIBLE THROUGH 1 AM CDT. RUNOFF FROM THESE THUNDERSTORMS 
WILL CONTINUE TO POSE A THREAT FOR FLASH FLOODING PAST MIDNIGHT.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SERENA...
YORKVILLE...SHERIDAN...OTTAWA...NEWARK AND MORRIS.

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

LAT...LON 4114 8916 4111 8866 4118 8828 4170 8828
      4153 8886

$$

MARSILI
000 
WGUS73 KLOT 230541
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1241 AM CDT THU AUG 23 2007

ILC063-093-099-230645-
GRUNDY IL-KENDALL IL-LA SALLE IL-
1241 AM CDT THU AUG 23 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 AM CDT FOR LA
SALLE...KENDALL AND GRUNDY COUNTIES...

AT 1241 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
LIGHT TO MODERATE RAIN ACROSS THE WARNED AREA...WHICH WILL END BY 
130 AM. RADAR ESTIMATES BETWEEN TWO AND THREE INCHES OF RAIN HAS 
FALLEN ACROSS SOUTHERN LA SALLE AND NORTHWEST GRUNDY COUNTIES. HIGH 
WATER AND FLOOD WATERS WILL SLOWLY RECEDE DURING THE EARLY MORNING 
HOURS.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
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. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 4114 8916 4111 8866 4118 8828 4170 8828
      4153 8886

$$
000 
WGUS73 KLOT 230647
FFSLOT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
146 AM CDT THU AUG 23 2007

ILC063-093-099-230700-
GRUNDY IL-KENDALL IL-LA SALLE IL-
146 AM CDT THU AUG 23 2007

...THE FLASH FLOOD WARNING HAS EXPIRED FOR LA SALLE...KENDALL AND
GRUNDY COUNTIES...

RAIN HAS ENDED ACROSS THE WARNED AREA AND NO ADDITIONAL REPORTS OF 
FLOODING HAVE BEEN RECEIVED. ADDITIONAL SHOWERS AND THUNDERSTORMS 
WILL BE POSSIBLE THROUGH SUNRISE...WHICH MAY CAUSE NEW FLOODING.

LAT...LON 4114 8916 4111 8866 4118 8828 4170 8828
      4153 8886

$$

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

Hazardous weather outlook, Aug 22, 4:30 PM CDT, 5 hours 20 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
430 PM CDT WED AUG 22 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
230945-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
430 PM CDT WED AUG 22 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH
CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...TONIGHT.

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS EVENING...WITH
THE GREATEST COVERAGE OF THESE THUNDERSTORMS EXPECTED CLOSER TO THE
ILLINOIS WISCONSIN STATELINE. THERE IS A SLIGHT RISK OF SEVERE
THUNDERSTORMS...MAINLY THIS EVENING...GENERALLY NORTH OF A LINE
DIXON TO DEKALB TO WAUKEGAN. THE MAIN THREAT WILL BE DAMAGING WINDS.

THERE IS A POTENTIAL FOR HEAVY RAINFALL TONIGHT...ESPECIALLY CLOSER
TO THE ILLINOIS WISCONSIN STATELINE. GIVEN SATURATED SOIL CONDITIONS
FROM THE RECENT HEAVY RAINS...ADDITIONAL HEAVY RAINFALL TONIGHT MAY
LEAD TO FLOODING PROBLEMS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THERE IS A GOOD CHANCE OF PERIODIC THUNDERSTORMS THURSDAY THROUGH
FRIDAY NIGHT. HEAVY RAINFALL WILL BE POSSIBLE DURING THIS PERIOD.
THERE IS THE POTENTIAL THAT STRONGER STORMS COULD PRODUCE DAMAGING
WINDS OR LARGE HAIL. THERE IS ALSO THE POTENTIAL FOR ADDITIONAL
SIGNIFICANT RAINFALL. GIVEN THE ALREADY SATURATED SOIL CONDITIONS
FROM RECENT HEAVY RAINFALL...ANY AREAS THAT EXPERIENCE MULTIPLE
ROUNDS OF HEAVY RAINFALL COULD EXPERIENCE SIGNIFICANT FLOODING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NECESSARY THIS EVENING ACROSS FAR NORTHERN
ILLINOIS. IN ADDITION...ANY REPORTS OF RAINFALL AMOUNTS OR FLOODING
WILL BE APPRECIATED TONIGHT THROUGH FRIDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ740>745-766-230945-
WINTHROP HARBOR TO WILMETTE HARBOR IL-
WILMETTE HARBOR TO NORTHERLY ISLAND IL-
NORTHERLY ISLAND TO CALUMET HARBOR IL-
CALUMET HARBOR IL TO GARY IN-
GARY INDIANA TO BURNS HARBOR-
BURNS HARBOR TO MICHIGAN CITY-
LAKE MICHIGAN IL AND IN OPEN WATERS-
430 PM CDT WED AUG 22 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS
AND INDIANA WATERS OF LAKE MICHIGAN.

.DAY ONE...TONIGHT.

THERE IS A CHANCE OF THUNDERSTORMS TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

ONE OR MORE PERIODS OF THUNDERSTORMS CAN BE EXPECTED FROM
THURSDAY THROUGH FRIDAY NIGHT...WITH THE POTENTIAL FOR THE
STRONGER STORMS TO PRODUCE STRONG WIND GUSTS.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

In the hours before

Local storm report, Aug 22, 8:44 PM CDT, 1 hour 6 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
844 PM CDT WED AUG 22 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0825 PM     TSTM WND DMG     POLO                    41.98N 89.58W
08/22/2007                   OGLE               IL   LAW ENFORCEMENT

            TREES DOWN ON POWER LINES.

&&

NMARSILI
Local storm report, Aug 22, 9:21 PM CDT, 29 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
921 PM CDT WED AUG 22 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0910 PM     TSTM WND GST     1 S EARLVILLE           41.57N 88.92W
08/22/2007  E60 MPH          LA SALLE           IL   TRAINED SPOTTER

&&

NMARSILI
Local storm report, Aug 22, 9:42 PM CDT, 8 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
942 PM CDT WED AUG 22 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0925 PM     TSTM WND GST     MARSEILLES              41.33N 88.69W
08/22/2007  M58.00 MPH       LA SALLE           IL   MESONET

0939 PM     TSTM WND GST     SANDWICH                41.65N 88.62W
08/22/2007  M45.00 MPH       DE KALB            IL   EMERGENCY MNGR

&&

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 8:36 PM CDTSevere Thunderstorm WarningLOTLee54 min
Aug 22, 8:37 PM CDTSevere Thunderstorm WarningLOTOgle26 min
Aug 22, 8:47 PM CDTSevere Thunderstorm WarningLOTDeKalb, LaSalle73 min
Aug 22, 9:22 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall38 min
Aug 22, 9:27 PM CDTSevere Thunderstorm WarningLOTKane48 min
Aug 22, 9:29 PM CDTRiver Flood WarningLOTWinnebago9 days
Aug 22, 9:29 PM CDTRiver Flood WarningLOTWinnebago25 hr
Aug 22, 9:42 PM CDTSevere Thunderstorm WarningLOTWill93 min
Aug 22, 10:02 PM CDTSpecial Marine WarningLOT118 min
Aug 22, 10:06 PM CDTSevere Thunderstorm WarningLOTCook, DuPage66 min
Aug 22, 10:10 PM CDTRiver Flood AdvisoryLOTLaSalle24 hr
Aug 22, 10:42 PM CDTFlash Flood WarningLOTCook, Will4 hr
Aug 23, 3:22 AM CDTSevere Thunderstorm WarningLOTDeKalb, Kane23 min
Aug 23, 4:15 AM CDTSpecial Marine WarningLOT45 min
Aug 23, 10:58 AM CDTRiver Flood WarningLOTCook4 days
Aug 23, 12:57 PM CDTFlash Flood WatchLOTBoone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more40 hr
Aug 23, 1:09 PM CDTSevere Thunderstorm WarningLOTLee, Ogle96 min
Aug 23, 1:45 PM CDTSevere Thunderstorm WarningLOTLaSalle, Livingston77 min
Aug 23, 1:47 PM CDTSevere Thunderstorm WarningLOTDeKalb58 min
Aug 23, 2:06 PM CDTSevere Thunderstorm WarningLOTKane75 min
Aug 23, 2:18 PM CDTSpecial Marine WarningLOT117 min
Aug 23, 2:27 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall57 min
Aug 23, 2:29 PM CDTTornado WarningLOTDeKalb, Kane46 min
Aug 23, 2:31 PM CDTFlash Flood WarningLOTLee, Ogle3 hr
Aug 23, 2:40 PM CDTSevere Thunderstorm WarningLOTCook, Will95 min
Aug 23, 2:41 PM CDTSevere Thunderstorm WarningLOTDuPage64 min
Aug 23, 2:57 PM CDTSevere Thunderstorm WarningLOTCook78 min
Aug 23, 3:13 PM CDTTornado WarningLOTCook, DuPage39 min
Aug 23, 3:23 PM CDTTornado WarningLOTCook, Will29 min
Aug 23, 3:33 PM CDTSevere Thunderstorm WarningLOTKankakee22 min
Aug 23, 4:48 PM CDTSevere Thunderstorm WarningLOTKane42 min
Aug 23, 4:53 PM CDTSevere Thunderstorm WarningLOTCook67 min
Aug 23, 5:04 PM CDTFlash Flood WarningLOTCook, DeKalb, DuPage, Kane4 hr
Aug 23, 5:05 PM CDTSevere Thunderstorm WarningLOTLee39 min
Aug 23, 5:24 PM CDTSpecial Marine WarningLOT2 hr
Aug 23, 5:34 PM CDTSevere Thunderstorm WarningLOTDuPage, Kane54 min
Aug 23, 5:37 PM CDTRiver Flood WarningLOTDeKalb3 days
Aug 23, 5:47 PM CDTSevere Thunderstorm WarningLOTKendall, LaSalle58 min
Aug 23, 6:21 PM CDTSevere Thunderstorm WarningLOTWill54 min
Aug 23, 6:26 PM CDTFlash Flood WarningLOTGrundy, Kendall, LaSalle, Will4 hr
Aug 23, 6:34 PM CDTSpecial Marine WarningLOT108 min
Aug 23, 6:44 PM CDTFlash Flood WarningLOTCook4 hr
Aug 23, 6:44 PM CDTSevere Thunderstorm WarningLOTCook61 min
Aug 23, 6:50 PM CDTSevere Thunderstorm WarningLOTGrundy, Kankakee, Will70 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.