Alert archive / Illinois / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 22, NWS Chicago, IL

May 15, 2007Will County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 15, 2007, 1:49 PM CDT for Will County, Illinois. It was in force for 41 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: May 15, 2007, 1:49 PM CDT (18:49 UTC)
Expired: May 15, 2007, 2:30 PM CDT
In force: 41 min
Issued by: NWS Chicago, IL
Area: Counties, with a storm outline in the text

County Will County, IL

The radar

The Chicago radar (KLOT), 20 km from the middle of the area, began a volume at 18:51 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

Lincoln, IL (KILX), launched 12:00Z, 6.8 hours before the alert went out and 153 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: 20 J/kg
Mixed-layer CIN: -273 J/kg
Mixed-layer LCL: 1998 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 49 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 May 15, 1:15 PM CDT, 34 minutes earlier.

Area forecast discussion, May 15, 1:15 PM CDT, 34 minutes before

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Hazardous weather outlook, May 15, 4:30 AM CDT, 9 hours 19 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
430 AM CDT TUE MAY 15 2007

ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011-
019-160930-
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-
430 AM CDT TUE MAY 15 2007

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

.DAY ONE... TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTH AND EAST OF A
LINE FROM WAUKEGAN TO BURLINGTON TO DEKALB TO PAW PAW.  THE MAIN
SEVERE THREAT WILL BE DAMAGING WIND AND HAIL.

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NECESSARY ON TUESDAY.

&&

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

LMZ740>745-766-160930-
WINTHROP HARBOR IL TO MICHIGAN CITY IN-
LAKE MICHIGAN-
430 AM CDT TUE MAY 15 2007

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

.DAY ONE... TODAY AND TONIGHT

A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE NEARSHORE WATERS
THROUGH TUESDAY MORNING. THERE IS A CHANCE OF THUNDERSTORMS TUESDAY.
THE MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS AND HAIL.

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

&&

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

HALBACH

The office that day

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

Issued	Product	Office	Counties	Lasted
May 15, 1:36 PM CDT	Severe Thunderstorm Warning	LOT	Grundy	39 min
May 15, 2:11 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee	34 min
May 15, 2:33 PM CDT	Tornado Warning	LOT	Will	18 min
May 15, 2:45 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois	46 min
May 15, 2:54 PM CDT	Special Marine Warning	LOT		66 min
May 15, 2:54 PM CDT	Special Marine Warning	LOT		66 min
May 15, 3:13 PM CDT	Severe Thunderstorm Warning	LOT	Iroquois	43 min
May 15, 4:17 PM CDT	Severe Thunderstorm Warning	LOT	Will	12 min
May 15, 2:49 PM CDT	Severe Thunderstorm Warning	LOT	Lake	26 min
May 15, 3:03 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	31 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2007 Every 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.