Alert archive / Illinois / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 9, NWS Chicago, IL

April 6, 2010Cook County, Lake County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Apr 6, 2010, 1:23 AM CDT for Cook County, Lake County, Illinois. It was in force for 37 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
Apr 6, 2010, 1:23 AM CDT (06:23 UTC)
Expired
Apr 6, 2010, 2:00 AM CDT
In force
37 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
0.5 in
Wind
70.0 mph

Counties Cook County, IL, Lake County, IL

The radar

The Chicago radar (KLOT), 64 km from the middle of the area, began a volume at 06:25 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
Apr 5, 11:07 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 6.4 hours before the alert went out and 234 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, Davenport, at 00:00Z on 2010-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 00:00Z on 2010-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 323 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1762 m above ground
0-6 km bulk shear
76 kt
0-1 km storm-relative helicity
323 m²/s²
0-3 km storm-relative helicity
584 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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 Apr 6, 12:38 AM CDT, 45 minutes earlier.

Area forecast discussion, Apr 6, 12:38 AM CDT, 45 minutes before
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Hazardous weather outlook, Apr 5, 9:25 PM CDT, 3 hours 58 minutes before
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In the hours before

Local storm report, Apr 6, 12:28 AM CDT, 55 minutes before
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Local storm report, Apr 6, 12:37 AM CDT, 46 minutes before
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Local storm report, Apr 6, 1:01 AM CDT, 22 minutes before
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Local storm report, Apr 6, 1:02 AM CDT, 21 minutes before
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Local storm report, Apr 6, 1:16 AM CDT, 7 minutes before
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<body>
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      <h1 id="headline">This service is currently unavailable.</h1>
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      <p id="message2">
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Local storm report, Apr 6, 1:17 AM CDT, 6 minutes before
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      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 5, 8:49 PM CDTSpecial Weather StatementLOTOgle26 min
Apr 5, 8:55 PM CDTSevere Thunderstorm WarningLOTOgle35 min
Apr 5, 9:02 PM CDTSpecial Marine WarningLOT88 min
Apr 5, 9:17 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Ogle, Winnebago28 min
Apr 5, 9:39 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Kane, McHenry, Winnebago51 min
Apr 5, 9:56 PM CDTSevere Thunderstorm WarningLOTDeKalb, Kane34 min
Apr 5, 10:06 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Kane, Lake, McHenry54 min
Apr 5, 10:07 PM CDTSpecial Marine WarningLOT98 min
Apr 5, 10:58 PM CDTSevere Thunderstorm WarningLOTCook17 min
Apr 5, 11:55 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Lee, Ogle, Winnebago65 min
Apr 6, 12:36 AM CDTSevere Thunderstorm WarningLOTBoone, Cook, DeKalb, Kane, Lake, Lee and 1 more54 min
Apr 6, 12:44 AM CDTSpecial Marine WarningLOT106 min
Apr 6, 3:26 AM CDTSmall Craft AdvisoryLOT22 hr
Apr 6, 5:36 AM CDTSevere Thunderstorm WarningLOTBoone, Lee, Ogle, Winnebago54 min
Apr 6, 6:11 AM CDTSpecial Marine WarningLOT115 min
Apr 6, 6:29 AM CDTSevere Thunderstorm WarningLOTBoone, Cook, DeKalb, DuPage, Kane, Kendall and 7 more61 min
Apr 6, 7:29 AM CDTSevere Thunderstorm WarningLOTLake13 min
Apr 6, 7:32 AM CDTSevere Thunderstorm WarningLOTCook, DuPage26 min
Apr 6, 8:03 AM CDTSpecial Marine WarningLOT57 min
Apr 6, 9:04 AM CDTSpecial Weather StatementLOTPorter26 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2010Every severe thunderstorm warning in 2010

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.