Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1773

July 28, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2011, 2:47 PM CDT for 4 states. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: Jul 28, 2011, 2:47 PM CDT (19:47 UTC)
Expired: Jul 28, 2011, 4:45 PM CDT
In force: 118 min
Issued by: the Storm Prediction Center

All 53 counties

Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Cherokee County, IA, Crawford County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mitchell County, IA, Monona County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Winona County, MN, Burt County, NE, Cuming County, NE, Dakota County, NE, Dodge County, NE, Stanton County, NE, Thurston County, NE, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Trempealeau County, WI

The radar

The Des Moines radar (KDMX), 158 km from the middle of the area, began a volume at 19:49 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, 7.8 hours before the alert went out and 198 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: 1122 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 676 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: -44 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: -0.3
Supercell composite: -1.3

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
Jul 27, 7:43 PM CDT	Tornado Watch	SPC	Cedar, Clinton, Delaware, Dubuque, Jackson, Jones	5 hr
Jul 27, 9:43 PM CDT	Mesoscale Discussion	SPC	Cedar, Clinton, Delaware, Dubuque, Jackson, Jones	62 min
Jul 28, 12:36 AM CDT	Mesoscale Discussion	SPC	Buchanan, Clinton, Delaware, Dubuque, Jackson, Jones and 1 more	84 min
Jul 28, 5:40 PM CDT	Mesoscale Discussion	SPC	Appanoose, Cedar, Clinton, Davis, Decatur, Des Moines and 14 more	95 min
Jul 28, 4:05 PM CDT	Mesoscale Discussion	SPC	Buffalo, Chase, Dawson, Dundy, Franklin, Frontier and 13 more	115 min

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Minnesota, 2011 Mesoscale Discussions in Wisconsin, 2011 Every mesoscale discussion in 2011

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.