Alert archive / Illinois / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 62, NWS Chicago, IL

August 22, 2001Livingston County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 22, 2001, 7:46 PM CDT for Livingston County, Illinois. It was in force for 44 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 22, 2001, 7:46 PM CDT (00:46 UTC)
Expired: Aug 22, 2001, 8:30 PM CDT
In force: 44 min
Issued by: NWS Chicago, IL
Area: Whole counties

County Livingston County, IL

The radar

The Chicago radar (KLOT), 89 km from the middle of the area, began a volume at 00:48 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.

Issued	Product	Office	Lasted
Aug 22, 2:00 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.8 hours before the alert went out and 83 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: 2203 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 1637 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.2

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, 5 hours 13 minutes earlier.

Area forecast discussion, Aug 22, 2:33 PM CDT, 5 hours 13 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

Local storm report, Aug 22, 5:28 PM CDT, 2 hours 18 minutes before

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Local storm report, Aug 22, 6:05 PM CDT, 1 hour 41 minutes before

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        The site you requested is temporarily down for maintenance or an unexpected outage.
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Nearby

Severe Thunderstorm Warnings in Illinois, 2001 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.