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Winter Weather Advisory 21, NWS Des Moines, IA

December 18, 20257 counties in Iowa

NWS Des Moines, IA issued this winter weather advisory at Dec 18, 2025, 11:00 AM CST for 7 counties in Iowa. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued: Dec 18, 2025, 11:00 AM CST (17:00 UTC)
Expired: Dec 18, 2025, 3:59 PM CST
In force: 5 hr
Issued by: NWS Des Moines, IA

Counties Cerro Gordo County, IA, Emmet County, IA, Hancock County, IA, Kossuth County, IA, Palo Alto County, IA, Winnebago County, IA, Worth County, IA

The radar

The Des Moines radar (KDMX), 167 km from the middle of the area, began a volume at 16:58 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

Minneapolis, MN (KMPX), launched 12:00Z, 5.0 hours before the alert went out and 183 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1041 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: -204 m²/s²
0-3 km storm-relative helicity: 58 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 winter weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before this winter weather advisory went out at Dec 18, 5:40 AM CST, 5 hours 20 minutes earlier.

Area forecast discussion, Dec 18, 5:40 AM CST, 5 hours 20 minutes before

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Hazardous weather outlook, Dec 18, 6:54 AM CST, 4 hours 6 minutes before

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In the hours before

Special weather statement, Dec 18, 5:54 AM CST, 5 hours 6 minutes before

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<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 18, 3:59 PM CST	Blizzard Warning	DMX	Bremer, Butler, Cerro Gordo, Emmet, Franklin, Hancock and 7 more	5 hr
Dec 18, 3:59 PM CST	Winter Storm Warning	DMX	Black Hawk, Grundy, Hamilton, Hardin, Marshall, Tama and 1 more	5 hr

Nearby

Winter Weather Advisories in Iowa, 2025 Every winter weather advisory in 2025

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.