Alert archive / Iowa / Special Weather Statements in 2017

Special Weather Statement, NWS Des Moines, IA

August 21, 20175 counties in Iowa

NWS Des Moines, IA issued this special weather statement at Aug 21, 2017, 6:52 PM CDT for 5 counties in Iowa. It was in force for 68 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 21, 2017, 6:52 PM CDT (23:52 UTC)
Expired: Aug 21, 2017, 8:00 PM CDT
In force: 68 min
Issued by: NWS Des Moines, IA

Counties Clarke County, IA, Lucas County, IA, Madison County, IA, Union County, IA, Warren County, IA

The radar

The Des Moines radar (KDMX), 62 km from the middle of the area, began a volume at 23:53 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

Omaha, NE (KOAX), launched 12:00Z, 11.9 hours before the alert went out and 220 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: 107 J/kg
Mixed-layer CIN: -350 J/kg
Mixed-layer LCL: 1132 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 209 m²/s²
0-3 km storm-relative helicity: 421 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 11.7

Open this sounding in Storm Lab

The text

As transmitted.

<!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>

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 21, 6:33 PM CDT, 19 minutes earlier.

Area forecast discussion, Aug 21, 6:33 PM CDT, 19 minutes before

<!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>

Hazardous weather outlook, Aug 21, 4:14 PM CDT, 2 hours 38 minutes before

Hazardous Weather Outlook
National Weather Service Des Moines IA
414 PM CDT Mon Aug 21 2017

IAZ004>007-015>017-023>026-033>036-044>046-222115-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Sac-Calhoun-Webster-Hamilton-
Crawford-Carroll-Greene-
414 PM CDT Mon Aug 21 2017

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Tonight

There is a slight risk for severe storms through this evening.
All modes of severe weather is possible along with heavy rainfall
which could lead to localized flooding west.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Scattered non-severe thunderstorms are possible Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this evening.

IAZ027-028-037>039-047>050-057>062-070>075-081>086-092>097-222115-
Butler-Bremer-Hardin-Grundy-Black Hawk-Boone-Story-Marshall-Tama-
Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek-Cass-Adair-Madison-
Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-Monroe-Wapello-
Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
414 PM CDT Mon Aug 21 2017

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Tonight

Showers and thunderstorms are likely through tonight. A few storms
could be strong, with strong winds and small hail the main
threats. Localized urban and small stream flooding is
possible...especially west.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Scattered non-severe thunderstorms are possible Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely not be needed this evening, and
will not be needed the rest of the week.

Kotenberg

In the hours before

Special weather statement, Aug 21, 5:37 PM CDT, 1 hour 15 minutes before

<!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>

Special weather statement, Aug 21, 6:04 PM CDT, 48 minutes before

<!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>

Special weather statement, Aug 21, 6:16 PM CDT, 36 minutes before

<!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>

Special weather statement, Aug 21, 6:26 PM CDT, 26 minutes before

<!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>

Special weather statement, Aug 21, 6:38 PM CDT, 14 minutes before

<!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>

Special weather statement, Aug 21, 6:52 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service Des Moines IA
652 PM CDT MON AUG 21 2017

IAZ071>073-082>084-220100-
Clarke IA-Adair IA-Lucas IA-Union IA-Madison IA-Warren IA-
652 PM CDT MON AUG 21 2017

...Gusty Winds Moving Southward Into South Central Iowa...

At 652 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Indianola to near Greenfield. Movement was
southeast at 30 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Indianola, Creston, Winterset, Osceola, Chariton, Green Valley Lake,
Lakeside Casino, Avenue Of The Saints Event Center, Afton, Milo,
Murray, St. Charles, New Virginia, Truro, Martensdale, Orient,
Lacona, Lorimor, Lucas and Woodburn.

LAT...LON 4128 9448 4140 9355 4117 9333 4116 9333
      4116 9331 4102 9318 4090 9434
TIME...MOT...LOC 2352Z 335DEG 25KT 4136 9364 4126 9441

Ansorge

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 11:03 PM CDT	Special Weather Statement	DMX	Crawford	27 min
Aug 20, 11:05 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Crawford, Sac	40 min
Aug 21, 12:32 AM CDT	Flash Flood Warning	DMX	Crawford	6 hr
Aug 21, 1:27 AM CDT	Special Weather Statement	DMX	Audubon, Guthrie	33 min
Aug 21, 1:31 AM CDT	Flash Flood Warning	DMX	Audubon, Carroll, Crawford, Guthrie	6 hr
Aug 21, 1:53 AM CDT	Special Weather Statement	DMX	Cass	22 min
Aug 21, 1:55 AM CDT	Severe Thunderstorm Warning	DMX	Emmet, Palo Alto	35 min
Aug 21, 2:07 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Audubon, Cass, Guthrie	53 min
Aug 21, 2:46 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Cass, Guthrie, Madison, Union	44 min
Aug 21, 3:02 AM CDT	Special Weather Statement	DMX	Kossuth	43 min
Aug 21, 3:30 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Ringgold, Taylor, Union	32 min
Aug 21, 9:43 AM CDT	Special Weather Statement	DMX	Calhoun, Humboldt, Pocahontas, Webster	62 min
Aug 21, 11:23 AM CDT	Special Weather Statement	DMX	Humboldt, Pocahontas	52 min
Aug 21, 1:39 PM CDT	Special Weather Statement	DMX	Emmet, Kossuth, Palo Alto	66 min
Aug 21, 2:02 PM CDT	Severe Thunderstorm Warning	DMX	Emmet, Kossuth, Palo Alto	29 min
Aug 21, 3:43 PM CDT	Special Weather Statement	DMX	Calhoun, Carroll, Crawford, Emmet, Humboldt, Kossuth and 4 more	77 min
Aug 21, 5:03 PM CDT	Special Weather Statement	DMX	Audubon, Boone, Cass, Dallas, Greene, Guthrie and 4 more	57 min
Aug 21, 5:37 PM CDT	Special Weather Statement	DMX	Boone, Grundy, Hamilton, Hardin, Story	53 min
Aug 21, 6:04 PM CDT	Special Weather Statement	DMX	Jasper, Polk	41 min
Aug 21, 6:16 PM CDT	Special Weather Statement	DMX	Madison, Warren	44 min
Aug 21, 6:26 PM CDT	Special Weather Statement	DMX	Black Hawk, Grundy, Marshall, Tama	64 min
Aug 21, 6:38 PM CDT	Special Weather Statement	DMX	Jasper, Mahaska, Marion	52 min
Aug 21, 6:58 PM CDT	Special Weather Statement	DMX	Poweshiek	47 min

Nearby

Special Weather Statements in Iowa, 2017 Every special weather statement in 2017

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.