Alert archive / Illinois / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 159, NWS Chicago, IL

September 25, 2007Cook County, Will County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Sep 25, 2007, 3:29 PM CDT for Cook County, Will County, Illinois. It was in force for 28 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
Sep 25, 2007, 3:29 PM CDT (20:29 UTC)
Expired
Sep 25, 2007, 3:57 PM CDT
In force
28 min
Issued by
NWS Chicago, IL
Area
Counties, with a storm outline in the text

Counties Cook County, IL, Will County, IL

The radar

The Chicago radar (KLOT), 24 km from the middle of the area, began a volume at 20:32 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
Sep 25, 2:59 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 8.5 hours before the alert went out and 182 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 2007-09-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1485 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 2007-09-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -76 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
1485 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
726 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
-76 m²/s²
0-3 km storm-relative helicity
-22 m²/s²
Significant tornado parameter
-0.4
Supercell composite
-2.3

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 Sep 25, 3:10 PM CDT, 19 minutes earlier.

Area forecast discussion, Sep 25, 3:10 PM CDT, 19 minutes before
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Hazardous weather outlook, Sep 25, 5:30 AM CDT, 9 hours 59 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
530 AM CDT TUE SEP 25 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
252045-
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-
530 AM CDT TUE SEP 24 2007

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

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS WILL BECOME LIKELY ACROSS THE AREA THIS AFTERNOON. A
FEW THUNDERSTORMS COULD PRODUCE DAMAGING WINDS OR LARGE HAIL THIS
AFTERNOON INTO EARLY THIS EVENING SOUTHEAST OF A LINE FROM RACINE TO
BELVIDERE TO STERLING. THUNDERSTORMS WILL BE ENDING FROM NORTHWEST
TO SOUTHEAST THIS EVENING AS A COLD FRONT MOVES THROUGH THE AREA.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THERE IS A CHANCE OF THUNDERSTORMS SATURDAY NIGHT AND SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED THIS AFTERNOON.

&&

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

LMZ740>745-766-252045-
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 WINTHROP HARBOR IL EASTWARD TO THE MID POINT OF THE
LAKE AND SOUTHWARD TO MICHIGAN CITY MI BEYOND 5 NM FROM SHORE-
530 AM CDT TUE SEP 25 2007

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

.DAY ONE...TODAY AND TONIGHT.

THERE IS A CHANCE OF THUNDERSTORMS THIS MORNING...WITH THUNDERSTORMS
BECOMING LIKELY THIS AFTERNOON INTO THIS EVENING. SOME OF THE STORMS
COULD PRODUCE STRONG GUSTY WINDS AND ISOLATED LARGE HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THERE IS A CHANCE OF THUNDERSTORMS SATURDAY NIGHT AND SUNDAY.

&&

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

HALBACH

In the hours before

Local storm report, Sep 25, 2:22 PM CDT, 1 hour 7 minutes before
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Local storm report, Sep 25, 2:35 PM CDT, 54 minutes before
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Local storm report, Sep 25, 2:57 PM CDT, 32 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
257 PM CDT TUE SEP 25 2007

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

0215 PM     TSTM WND DMG     ELGIN                   42.04N 88.29W
09/25/2007                   KANE               IL   TRAINED SPOTTER

            N. WORTH AVE AND LARKIN. 4FT DIAMETER TREE DOWN. POWER
            LINES DOWN

&&

HALBACH
Local storm report, Sep 25, 3:05 PM CDT, 24 minutes before
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Local storm report, Sep 25, 3:17 PM CDT, 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
317 PM CDT TUE SEP 25 2007

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

0258 PM     TSTM WND GST     NORTHBROOK              42.13N 87.83W
09/25/2007  M51.00 MPH       COOK               IL   TRAINED SPOTTER

&&

ACS
Local storm report, Sep 25, 3:21 PM CDT, 8 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
321 PM CDT TUE SEP 25 2007

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

0200 PM     TSTM WND DMG     ROCKFORD                42.27N 89.06W
09/25/2007                   WINNEBAGO          IL   BROADCAST MEDIA

            LARGE TREE DOWN AT BROOKE RD AND SANER RD ON SOUTH SIDE
            OF ROCKFORD.

&&

ACS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 25, 1:29 PM CDTSevere Thunderstorm WarningLOTOgle, Winnebago46 min
Sep 25, 1:58 PM CDTSevere Thunderstorm WarningLOTBoone32 min
Sep 25, 2:41 PM CDTSpecial Marine WarningLOT94 min
Sep 25, 2:42 PM CDTSevere Thunderstorm WarningLOTCook, Lake48 min
Sep 25, 3:00 PM CDTSevere Thunderstorm WarningLOTLake23 min
Sep 25, 3:10 PM CDTSpecial Marine WarningLOT64 min
Sep 25, 3:22 PM CDTSevere Thunderstorm WarningLOTCook, DuPage21 min
Sep 25, 4:09 PM CDTSpecial Marine WarningLOT87 min
Sep 25, 4:18 PM CDTSpecial Marine WarningLOT57 min
Sep 25, 4:18 PM CDTSevere Thunderstorm WarningLOTLake, Porter45 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2007Every severe thunderstorm 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.