Alert archive / Illinois / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 60, NWS Chicago, IL

August 22, 2001Cook County, DuPage County, Kane County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 22, 2001, 5:51 PM CDT for Cook County, DuPage County, Kane County, Illinois. It was in force for 39 min. 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
Aug 22, 2001, 5:51 PM CDT (22:51 UTC)
Expired
Aug 22, 2001, 6:30 PM CDT
In force
39 min
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Cook County, IL, DuPage County, IL, Kane County, IL

The radar

The Chicago radar (KLOT), 32 km from the middle of the area, began a volume at 22:50 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
Aug 22, 5:55 PM CDTHail 1Carpentersville, IL
Aug 22, 6:15 PM CDTThunderstorm Wind 50 EMorton Grove, IL
Aug 22, 6:15 PM CDTHail 0.75Morton Grove, IL

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

IssuedProductOfficeLasted
Aug 22, 2:00 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.9 hours before the alert went out and 199 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 2001-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 743 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 2001-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 174 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
743 J/kg
Mixed-layer CIN
-306 J/kg
Mixed-layer LCL
1614 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
129 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 22, 2:33 PM CDT, 3 hours 18 minutes earlier.

Area forecast discussion, Aug 22, 2:33 PM CDT, 3 hours 18 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
233 PM CDT WED AUG 22 2001

FORECAST CONCERNS FOCUS ON POPS EARLY PERIODS AS WELL AS THREAT OF
SEVERE WEATHER TONIGHT. WARM FRONT PUSHED INTO SOUTHERN WISCONSIN
AND IS NOW STATIONARY ALONG WI/IL BORDER SOUTHWEST INTO CENTRAL IA.
WINDS HAVE RECOVERED BACK TO S/SW WITH TEMPS INTO THE 80S AND
DEWPOINTS WELL INTO THE 70S. ONLY BOUNDARY DETECTED LIES ACROSS
SOUTHERN FA BUT OTHERS LIKELY ABOUT AFTER MORNING CONVECTION.

DIFFERENCES SHOWING UP IN THE MODELS THIS RUN. AT 18Z...AVN SEEMS TO
HAVE BEST HANDLE ON SURFACE WINDS/LOCATION OF FRONT AS WELL AS
POSITION OF LOW ACROSS NE IA. AVN ALSO DID A BETTER JOB WITH
LOCATION OF CONVECTION THIS MORNING OVER SOUTHERN WI AND SOUTHWEST
MI. BY 00Z ETA LOOKS TOO FAR SOUTH WITH FRONT AND QPF. AVN FARTHER
NORTH AND LOOKS OVERALL BETTER WITH INSTABILITY. WILL TREND TOWARD
THE AVN AND NOW WITH SVR WX BOX OUT WILL GO CAT ENTIRE FA. WILL END
POPS LATE TONIGHT NORTHERN AREA AND CONTINUE POPS ALL NIGHT WITH
HEAVY RAIN MENTIONED ACROSS SOUTHERN FA. WILL ALSO KEEP LOW CHANCE
POP FOR ANY LEFT OVER RAIN SOUTHERN FA.

HIGH PRESSURE BUILDS IN ON THURS FROM UPPER LAKES AND WILL DRY
THINGS OUT UNTIL SAT WHEN NEXT SYSTEM APPROACHES. WILL REMOVE POPS
FROM FRI...KEEP FOR SAT AND INTRODUCE ON SUN. WILL STAY CLOSE TO
GUIDANCE EARLY PERIODS AND TREND WARMER TOWARD MAV LATER PERIODS.

.CHI...NONE.

CMS

In the hours before

Special weather statement, Aug 22, 11:56 AM CDT, 5 hours 55 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>002-010>011-019-
231100-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
1200 PM CDT/EST WED AUG 22 2001

FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE ENTIRE
AREA THROUGH TONIGHT.

LOW PRESSURE WAS OVER NORTHERN IOWA LATE THIS MORNING...WITH A
STATIONARY FRONT EXTENDING ACROSS FAR NORTHERN ILLINOIS.
THUNDERSTORMS THAT DEVELOPED ALONG THIS FRONT THIS MORNING HAVE
DISSIPATED. OUTFLOW BOUNDARIES FROM THESE THUNDERSTORMS HAVE PUSHED
SOUTH ACROSS NORTHERN AND CENTRAL ILLINOIS.

THIS STATIONARY FRONT WILL SLOWLY MOVE SOUTH AS A WEAK COLD FRONT
LATER THIS AFTERNOON AND THIS EVENING. THUNDERSTORMS ARE EXPECTED TO
REDEVELOP THIS AFTERNOON AHEAD OF THIS FRONT...ACROSS NORTHERN
ILLINOIS...AND MOVE SOUTHEAST INTO CENTRAL ILLINOIS AND NORTHWEST
INDIANA THIS EVENING. THE MAIN SEVERE WEATHER THREAT FROM THESE
THUNDERSTORMS WILL BE DAMAGING WINDS ALONG WITH HEAVY RAINFALL.

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND THIS EVENING.

STAY TUNED TO NOAA WEATHER RADIO...OR OTHER MEDIA OUTLETS...FOR
LATER STATEMENTS FROM THE NATIONAL WEATHER SERVICE.

CMS
Local storm report, Aug 22, 5:28 PM CDT, 23 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 5:08 PM CDTSevere Thunderstorm WarningLOTBoone, McHenry37 min
Aug 22, 6:17 PM CDTSevere Thunderstorm WarningLOTIroquois43 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2001Every severe thunderstorm warning in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.