Alert archive / Illinois / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 75, NWS Chicago, IL

July 6, 2003Lee County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 6, 2003, 8:39 PM CDT for Lee County, Illinois. It was in force for 36 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: Jul 6, 2003, 8:39 PM CDT (01:39 UTC)
Expired: Jul 6, 2003, 9:15 PM CDT
In force: 36 min
Issued by: NWS Chicago, IL
Area: Counties, with a storm outline in the text

County Lee County, IL

The radar

The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 01:42 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

Davenport, (KDVN), launched 00:00Z, 1.7 hours before the alert went out and 101 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2676 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1259 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 157 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.9

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 Jul 6, 2:00 PM CDT, 6 hours 39 minutes earlier.

Area forecast discussion, Jul 6, 2:00 PM CDT, 6 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
200 PM CDT SUN JUL 6 2003

DISCUSSION FOR AFTERNOON GRIDS AND ZONES...

SVR WX IN PROGRESS.  SEE SWODY1 AND HWOLOT FOR DETAILS ON TSTM
DVLPMT NXT 18 HRS.  HAVE CHGD LTL IN GRIDS/ZONES XCP FOR WED-THU.
HAVE INTODUCED MENTION OF PRECIP THIS PERIOD BASED ON 12Z MDL RUNS
BRINGING ANOTHER COUPLE OF SHORT WAVES THRU NWLY H5 FLO DURG THIS
PERIOD.  OTRW LTL CHG TO FCST.

.CHI...NONE

MERZLOCK

Hazardous weather outlook, Jul 6, 11:00 AM CDT, 9 hours 39 minutes before

ILZ003>006-008-010>014-019-020>023-032-033-039-INZ001-002-010-011-019
-071100-

HAZARDOUS WEATHER OUTLOOK/SUPPLEMENTAL
NATIONAL WEATHER SERVICE CHICAGO IL
1100 AM CDT SUN JUL 6 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
ILLINOIS...NORTHWEST INDIANA...AND THE ADJACENT WATERS OF LAKE
MICHIGAN.

.DAY ONE... THIS AFTERNOON AND TONIGHT

A WATCH BOX WILL BE ISSUED FOR THE ENTIRE AREA AROUND NOON.

FOLLOWING A LULL IN ACTIVITY THIS EVENING...THERE IS A MODERATE RISK
OF SEVERE THUNDERSTORMS AFTER MIDNIGHT IN AREAS NORTH OF ABOUT I
80...AND A SLIGHT RISK OF SEVERE STORMS SOUTH OF I 80.

DAMAGING WINDS WILL BE THE MAIN THREAT THIS AFTERNOON WITH ISOLATED
SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND TORNADOES.

THE PRIMARY THREAT TONIGHT WILL BE DAMAGING WINDS AND LARGE HAIL.

A MESOSCALE STORM SYSTEM OVER NORTHEAST IOWA LATE THIS MORNING
WILLBE TRACKING EASTWARD ACROSS SOUTHERN WISCONSIN THIS AFTERNOON.
AS IT DOES SO IT WILL BE MOVING INTO VERY UNSTABLE AIR OVER NORTHERN
ILLINOIS AND NORTHWEST INDIANA.  DUE TO THE DEGREE OF INSTABILITY IN
PLACE...WITH SURFACE TEMPERATURES AROUND 90 AND DEW POINTS IN THE
LOWER AND MIDDLE 70S...SOME SUPERCELLS ARE POSSIBLE.  WIND SHEAR
THROUGH THE MID LEVELS OF THE ATMOSPHERE MAY PROVIDE AN ENVIRONMENT
FAVORABLE FOR ROTATION.

ANOTHER MESOSCALE WEATHER SYSTEM IS EXPECTED TO BLOW UP THIS
AFTERNOON AND EVENING AHEAD OF A COLD FRONT IN MINNESOTA AND TRACK
SOUTHEAST INTO OUR AREA AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN... MONDAY THROUGH SATURDAY

TEMPERATURES REACHING THE MID 90S...AND DEWPOINTS INTO THE 70S WILL
COMBINE TO PRODUCE HEAT INDICES APPROACHING 105 IN SOME AREAS.

PERIODS OF THUNDERSTORMS ARE LIKELY INTO WEDNESDAY MORNING.  SOME OF
THESE MAY BE SEVERE WITH ADDITIONAL HEAVY RAIN.  DRIER AND COOLER
AIR IS EXPECTED LATER WEDNESDAY THROUGH FRIDAY. MORE THUNDERSTORMS
ARE POSSIBLE SATURDAY.

SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON AND MAY BE NEEDED AGAIN
LATE TONIGHT...AFTER MIDNIGHT.

&&

           NWS CHICAGO WEBPAGE

    HTTP://WWW.CRH.NOAA.GOV/LOT (LOWER CASE)
OR  HTTP://WEATHER.NOAA.GOV/CHICAGO (LOWER CASE)

MERZLOCK

In the hours before

Local storm report, Jul 6, 6:18 PM CDT, 2 hours 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
618 PM CDT SUN JUL 06 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0500 PM    WHEELING                  IL   1 INCH HAIL
07/06/03   COOK                           LAKE-COOK RD AND RT 21.
                                          REPORTED BY HAM RADIO
                                          OPERATOR.

0502 PM    BUFFALO GROVE             IL   1 INCH HAIL
07/06/03   LAKE                           LAKE/COOK ROAD.
                                          REPORTED BY HAM RADIO
                                          OPERATOR.

0517 PM    BLOOMINGDALE              IL   1.75 INCH HAIL
07/06/03   DUPAGE                         ARMY TRAIL AND GARY
                                          AVE. CAROL STREAM. .
                                          REPORTED BY HAM RADIO
                                          OPERATOR.

0520 PM    WEST CHICAGO              IL   1 INCH HAIL
07/06/03   DUPAGE                         2 MI N OF RT 64 AND RT
                                          59. REPORTED BY STORM
                                          SPOTTER.

0526 PM    GLENDALE HGTS             IL   1.75 INCH HAIL
07/06/03   DUPAGE                         ALSO MINOR STREET
                                          FLOODING. REPORTED BY
                                          STORM SPOTTER.

0526 PM    ADDISON                   IL   1 INCH HAIL
07/06/03   DUPAGE                         AT RT 83 AND GRAND AVE.
                                          . REPORTED BY STORM
                                          SPOTTER.

0615 PM    ASHKUM                    IL   .88 INCH HAIL
07/06/03   IROQUOIS                       REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

Local storm report, Jul 6, 6:34 PM CDT, 2 hours 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
634 PM CDT SUN JUL 06 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0526 PM    WHEATON                   IL   .75 INCH HAIL
07/06/03   DUPAGE                         REPORTED BY STORM
                                          SPOTTER.

0530 PM    LOMBARD                   IL   1 INCH HAIL
07/06/03   DUPAGE                         REPORTED BY STORM
                                          SPOTTER.

Local storm report, Jul 6, 6:38 PM CDT, 2 hours 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
638 PM CDT SUN JUL 06 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0635 PM    JOLIET                    IL   .75 INCH HAIL
07/06/03   WILL                           REPORTED BY EMERGENCY
                                          MANAGEMENT.

Local storm report, Jul 6, 6:45 PM CDT, 1 hour 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
645 PM CDT SUN JUL 06 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0600 PM    CICERO                    IL   .88 INCH HAIL
07/06/03   COOK                           REPORTED BY STORM
                                          SPOTTER.

Local storm report, Jul 6, 6:56 PM CDT, 1 hour 43 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
656 PM CDT SUN JUL 06 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0615 PM    EVERGREEN PARK            IL   1 INCH HAIL
07/06/03   COOK                           REPORTED BY STORM
                                          SPOTTER.

0626 PM    10 W CHICAGO              IL   .75 INCH HAIL
07/06/03   COOK                           REPORTED BY STORM
                                          SPOTTER AT 87TH AND
                                          LAWNDALE.

Local storm report, Jul 6, 8:09 PM CDT, 30 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 7:11 PM CDT	Severe Thunderstorm Warning	LOT	Iroquois	49 min
Jul 6, 8:02 PM CDT	Severe Thunderstorm Warning	LOT	Iroquois	28 min
Jul 7, 7:21 AM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	39 min
Jul 7, 7:39 AM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Kane, Kendall, LaSalle, McHenry	51 min
Jul 7, 7:59 AM CDT	Special Marine Warning	LOT		61 min
Jul 7, 8:17 AM CDT	Severe Thunderstorm Warning	LOT	DuPage, Grundy, Will	43 min
Jul 7, 8:42 AM CDT	Severe Thunderstorm Warning	LOT	Cook	48 min
Jul 7, 9:00 AM CDT	Severe Thunderstorm Warning	LOT	Kankakee, Will	45 min
Jul 7, 9:05 AM CDT	Severe Thunderstorm Warning	LOT	LaSalle, Livingston	25 min
Jul 7, 9:09 AM CDT	Special Marine Warning	LOT		66 min
Jul 7, 9:27 AM CDT	Severe Thunderstorm Warning	LOT	Livingston	48 min
Jul 7, 9:13 AM CDT	Severe Thunderstorm Warning	LOT	Porter	47 min
Jul 7, 9:33 AM CDT	Severe Thunderstorm Warning	LOT	Jasper, Newton	42 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2003 Every severe thunderstorm warning in 2003

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.