Alert archive / Iowa / Mesoscale Discussions in 2014

Mesoscale Discussion 1694

September 9, 201417 counties in Iowa; Harrison County, Mercer County, Worth County, Missouri; 4 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Sep 9, 2014, 12:13 PM CDT for 17 counties in Iowa; Harrison County, Mercer County, Worth County, Missouri; 4 counties in Nebraska. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Sep 9, 2014, 12:13 PM CDT (17:13 UTC)
Expired: Sep 9, 2014, 1:15 PM CDT
In force: 62 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 24 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Harrison County, IA, Madison County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Harrison County, MO, Mercer County, MO, Worth County, MO, Burt County, NE, Cuming County, NE, Thurston County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 107 km from the middle of the area, began a volume at 17:17 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.

Tornado Watch 499Sep 9, 3:35 PM CDT

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 5.2 hours before the alert went out and 107 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: 1246 J/kg
Mixed-layer CIN: -266 J/kg
Mixed-layer LCL: 1436 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 96 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Sep 9, 3:06 PM CDT	Mesoscale Discussion	SPC	Adams, Decatur, Fremont, Mills, Montgomery, Page and 3 more	114 min
Sep 9, 3:34 PM CDT	Tornado Watch	SPC	Adair, Adams, Appanoose, Audubon, Cass, Clarke and 17 more	8 hr
Sep 9, 5:06 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Cass, Fremont, Guthrie and 9 more	54 min
Sep 9, 6:45 PM CDT	Mesoscale Discussion	SPC	Appanoose, Decatur, Fremont, Monroe, Page, Ringgold and 2 more	90 min
Sep 9, 9:44 AM CDT	Mesoscale Discussion	SPC	City of Saint Louis	2 hr
Sep 9, 1:25 PM CDT	Mesoscale Discussion	SPC	Benton, Boone, Callaway, Camden, Carter, Christian and 40 more	2 hr
Sep 9, 5:02 PM CDT	Mesoscale Discussion	SPC	Audrain, Jefferson, Lincoln, Monroe, Montgomery, Pike and 5 more	88 min
Sep 9, 3:36 PM CDT	Mesoscale Discussion	SPC	Chase, Dundy, Frontier, Hayes, Hitchcock, Keith and 3 more	114 min
Sep 9, 4:05 PM CDT	Severe Thunderstorm Watch	SPC	Chase, Dundy, Frontier, Hayes, Hitchcock, Lincoln and 2 more	7 hr
Sep 9, 6:17 PM CDT	Mesoscale Discussion	SPC	Dundy, Frontier, Furnas, Gosper, Harlan, Hayes and 3 more	88 min

Nearby

Mesoscale Discussions in Iowa, 2014 Mesoscale Discussions in Nebraska, 2014 Mesoscale Discussions in Missouri, 2014 Every mesoscale discussion in 2014

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.