Alert archive / Illinois / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 178, NWS Chicago, IL

August 17, 2004Grundy County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 17, 2004, 6:09 PM CDT for Grundy County, Illinois. It was in force for 66 min. 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 17, 2004, 6:09 PM CDT (23:09 UTC)
Expired
Aug 17, 2004, 7:15 PM CDT
In force
66 min
Issued by
NWS Chicago, IL
Area
Counties, with a storm outline in the text

County Grundy County, IL

The radar

The Chicago radar (KLOT), 45 km from the middle of the area, began a volume at 23:11 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 17, 1:20 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.2 hours before the alert went out and 127 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 2004-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 127 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 12:00Z on 2004-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 103 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
127 J/kg
Mixed-layer CIN
-124 J/kg
Mixed-layer LCL
932 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 17, 4:30 PM CDT, 1 hour 39 minutes earlier.

Area forecast discussion, Aug 17, 4:30 PM CDT, 1 hour 39 minutes before
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Hazardous weather outlook, Aug 17, 5:00 PM CDT, 1 hour 9 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
500 PM CDT TUE AUG 17 2004

ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011-019
-181100-
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
500 PM CDT TUE AUG 17 2004

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

.DAY ONE...TONIGHT

THERE IS A SLIGHT RISK OF SEVERE WEATHER EARLY THIS EVENING. THERE
WILL BE SCATTERED THUNDERSTORMS THIS EVENING SOUTHEAST OF A QUAD
CITIES
TO DEKALB TO WAUKEGAN LINE. SOME OF THE STORMS COULD PRODUCE STRONG
WINDS OR LARGE HAIL EARLY THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THERE IS CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON AND NIGHT.
THERE IS A SLIGHT RISK OF SEVERE WEATHER WITH THESE STORMS.

THERE IS ANOTHER CHANCE OF THUNDERSTORMS THURSDAY NIGHT AND
FRIDAY...AND AGAIN MONDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION NECESSARY THIS EVENING...AND MAY BE NEEDED
WEDNESDAY AFTERNOON AND EVENING.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)

LMZ740>746-766-181100-
WINTHROP HARBOR TO WILMETTE HARBOR-WILMETTE HARBOR TO NORTHERLY
ISLAND-NORTHERLY ISLAND TO CALUMET HARBOR-CALUMET HARBOR TO
GARY-GARY TO BURNS HARBOR-BURNS HARBOR TO MICHIGAN CITY-MICHIGAN
CITY TO NEW BUFFALO-LAKE MICHIGAN-
500 PM CDT TUE AUG 17 2004

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

.DAY ONE...TONIGHT

THERE WILL BE SCATTERED THUNDERSTORMS THIS EVENING. THERE IS A
SLIGHT RISK OF SEVERE WEATHER EARLY THIS EVENING. SOME OF THE STORMS
COULD PRODUCE STRONG WINDS OR LARGE HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THERE IS CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON AND NIGHT.
THERE IS A SLIGHT RISK OF SEVERE WEATHER WITH THESE STORMS.

THERE IS ANOTHER CHANCE OF THUNDERSTORMS FRIDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)

In the hours before

Local storm report, Aug 17, 5:28 PM CDT, 41 minutes before
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Local storm report, Aug 17, 5:37 PM CDT, 32 minutes before
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Local storm report, Aug 17, 5:40 PM CDT, 29 minutes before
PRELIMINARY LOCAL STORM REPORT ... CORRECTION
NATIONAL WEATHER SERVICE CHICAGO IL
540 PM CDT TUE AUG 17 2004

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

0515 PM     LIGHTNING        5 N PLAINFIELD          41.69N 88.20W
08/17/2004                   WILL               IL   EMERGENCY MNGR

            PERSON STRUCK BY LIGHTNING AT 119TH AND BOOK ROADS.
            NON-FATAL.

&&

KRAUSE
Local storm report, Aug 17, 5:46 PM CDT, 23 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
546 PM CDT TUE AUG 17 2004

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

0542 PM     TSTM WND GST     BRIDGEVIEW              41.74N 87.81W
08/17/2004  60 MPH           COOK               IL   TRAINED SPOTTER

            WINDS ESTIMATED TO 60 MPH AT 78TH AND 87TH STREETS.

0545 PM     HAIL             CHICAGO RIDGE           41.70N 87.78W
08/17/2004  0.88 INCH        COOK               IL   TRAINED SPOTTER

&&

KRAUSE
Special weather statement, Aug 17, 5:58 PM CDT, 11 minutes before
ILZ006-ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039-180000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
558 PM CDT TUE AUG 17 2004

ILZ006-010-011-180000-
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS CLEARED A PORTION OF
SEVERE THUNDERSTORM WATCH 756. COUNTIES CLEARED INCLUDE:

IN ILLINOIS:
DE KALB...LAKE...LEE...

THIS INCLUDES THE CITIES OF...DE KALB...DIXON...WAUKEGAN...

ILZ012>014-019>023-032-033-039-180000-
SEVERE THUNDERSTORM WATCH 756 REMAINS VALID UNTIL 700 PM CDT
TUESDAY FOR THE FOLLOWING COUNTIES:

IN ILLINOIS:
COOK...DU PAGE...FORD...GRUNDY...IROQUOIS...KANE...KANKAKEE...
KENDALL...LA SALLE...LIVINGSTON...WILL...

THIS INCLUDES THE CITIES OF...AURORA...CHICAGO...GIBSON CITY...
JOLIET...KANKAKEE...LA SALLE...MORRIS...NAPERVILLE...PONTIAC...
WATSEKA...YORKVILLE...
Local storm report, Aug 17, 6:02 PM CDT, 7 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
602 PM CDT TUE AUG 17 2004

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

0552 PM     HAIL             NAPERVILLE              41.76N 88.15W
08/17/2004  0.75 INCH        DUPAGE             IL   PUBLIC

&&

KRAUSE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 4:34 PM CDTSevere Thunderstorm WarningLOTLaSalle56 min
Aug 17, 5:12 PM CDTSevere Thunderstorm WarningLOTWill48 min
Aug 17, 5:22 PM CDTSevere Thunderstorm WarningLOTCook68 min
Aug 17, 5:45 PM CDTSpecial Marine WarningLOT60 min
Aug 17, 5:45 PM CDTSpecial Marine WarningLOT60 min
Aug 17, 5:45 PM CDTSpecial Marine WarningLOT60 min
Aug 17, 6:23 PM CDTSevere Thunderstorm WarningLOTLaSalle67 min
Aug 17, 6:45 PM CDTSpecial Marine WarningLOT45 min
Aug 17, 6:45 PM CDTSpecial Marine WarningLOT45 min
Aug 17, 6:05 PM CDTSevere Thunderstorm WarningLOTLake, Porter55 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2004Every severe thunderstorm warning in 2004

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.