Alert archive / Illinois / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 348, NWS Lincoln, IL

August 12, 2026Knox County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Aug 12, 2026, 7:44 AM CDT for Knox County, Illinois. It was in force for 61 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 12, 2026, 7:44 AM CDT (12:44 UTC)
Expired: Aug 12, 2026, 8:45 AM CDT
In force: 61 min
Issued by: NWS Lincoln, IL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Knox County, IL

The radar

The Quad Cities radar (KDVN), 82 km from the middle of the area, began a volume at 12:48 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 12, 6:41 AM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 0.7 hours before the alert went out and 80 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: 4572 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 679 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -14 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.4

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 Lincoln, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 12, 5:48 AM CDT, 1 hour 56 minutes earlier.

Area forecast discussion, Aug 12, 5:48 AM CDT, 1 hour 56 minutes before

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Hazardous weather outlook, Aug 12, 4:48 AM CDT, 2 hours 56 minutes before

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<html lang="en">
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  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
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</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <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.
      </p>
      <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 Lincoln, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 1:59 AM CDT	Heat Advisory	ILX	Cass, Christian, Clay, Crawford, Effingham, Jasper and 7 more	18 hr
Aug 12, 8:25 AM CDT	Severe Thunderstorm Warning	ILX	Marshall, Stark	53 min
Aug 12, 10:35 AM CDT	Severe Thunderstorm Warning	ILX	Vermilion	40 min
Aug 12, 11:47 AM CDT	Areal Flood Advisory	ILX	Knox, Peoria, Stark	3 hr
Aug 12, 1:39 PM CDT	Severe Thunderstorm Warning	ILX	Crawford, Lawrence	12 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2026 Every severe thunderstorm warning in 2026

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.