Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 372

April 18, 200426 counties in Iowa; 21 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2004, 4:15 PM CDT for 26 counties in Iowa; 21 counties in Minnesota. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Apr 18, 2004, 4:15 PM CDT (21:15 UTC)
Expired: Apr 18, 2004, 5:15 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 47 counties

Buena Vista County, IA, Calhoun County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Sioux County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN

The radar

The Minneapolis radar (KMPX), 175 km from the middle of the area, began a volume at 21:18 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.3 hours before the alert went out and 174 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: 680 J/kg
Mixed-layer CIN: -274 J/kg
Mixed-layer LCL: 697 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 361 m²/s²
0-3 km storm-relative helicity: 401 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

<!doctype html>
<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>
</html>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 17, 7:45 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Cerro Gordo, Chickasaw, Emmet, Floyd, Hancock and 7 more	5 hr
Apr 17, 9:31 PM CDT	Mesoscale Discussion	SPC	Allamakee, Cerro Gordo, Chickasaw, Emmet, Fayette, Floyd and 8 more	119 min
Apr 17, 10:05 PM CDT	Tornado Watch	SPC	Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 19 more	5 hr
Apr 17, 11:10 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cherokee, Clay, Dickinson, Lyon, O'Brien and 3 more	95 min
Apr 17, 11:35 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Dickinson, Lyon, O'Brien, Osceola, Sioux	5 hr
Apr 17, 11:50 PM CDT	Mesoscale Discussion	SPC	Cerro Gordo, Emmet, Hancock, Howard, Humboldt, Kossuth and 5 more	85 min
Apr 18, 4:40 PM CDT	Tornado Watch	SPC	Audubon, Buena Vista, Calhoun, Carroll, Cass, Cherokee and 29 more	5 hr
Apr 18, 12:30 AM CDT	Severe Thunderstorm Watch	SPC	Anoka, Carver, Chisago, Dakota, Goodhue, Hennepin and 11 more	5 hr
Apr 18, 2:37 AM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Big Stone, Brown, Carlton and 40 more	53 min
Apr 18, 4:43 AM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Carlton, Cass, Chisago, Crow Wing and 15 more	32 min
Apr 18, 8:04 AM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Carlton, Cass, Crow Wing, Douglas and 6 more	86 min
Apr 18, 12:39 PM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Big Stone, Carlton, Carver and 32 more	2 hr
Apr 18, 1:40 PM CDT	Tornado Watch	SPC	Aitkin, Anoka, Benton, Carlton, Carver, Chippewa and 32 more	6 hr
Apr 18, 2:20 PM CDT	Severe Thunderstorm Watch	SPC	Lincoln, Lyon, Pipestone, Rock	6 hr
Apr 18, 3:33 PM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 12 more	117 min
Apr 18, 5:23 PM CDT	Mesoscale Discussion	SPC	Lincoln, Lyon, Pipestone, Rock	2 hr
Apr 18, 6:35 PM CDT	Tornado Watch	SPC	Brown, Carver, Dakota, Goodhue, Hennepin, Le Sueur and 7 more	5 hr

Nearby

Mesoscale Discussions in Iowa, 2004 Mesoscale Discussions in Minnesota, 2004 Every mesoscale discussion in 2004

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.