Alert archive / Iowa / Tornado Warnings in 2024

Tornado Warning 61, NWS Omaha, NE

May 21, 2024Shelby County, Iowa

NWS Omaha, NE issued this tornado warning at May 21, 2024, 12:53 AM CDT for Shelby County, Iowa. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 21, 2024, 12:53 AM CDT (05:53 UTC)
Expired: May 21, 2024, 1:32 AM CDT
In force: 39 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Shelby County, IA

The radar

The Omaha radar (KOAX), 97 km from the middle of the area, began a volume at 05:57 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 20, 11:33 PM CDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 5.9 hours before the alert went out and 97 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: 1458 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 1666 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Omaha, NE wrote its last area forecast discussion before this tornado warning went out at May 21, 12:20 AM CDT, 33 minutes earlier.

Area forecast discussion, May 21, 12:20 AM CDT, 33 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, May 20, 3:46 PM CDT, 9 hours 7 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>

In the hours before

Local storm report, May 21, 12:07 AM CDT, 46 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>

Local storm report, May 21, 12:21 AM CDT, 32 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>

Local storm report, May 21, 12:28 AM CDT, 25 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>

Local storm report, May 21, 12:35 AM CDT, 18 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>

Local storm report, May 21, 12:36 AM CDT, 17 minutes before

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
1236 AM CDT Tue May 21 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1154 PM     Flash Flood      1 SE Elkhorn            41.27N 96.23W
05/20/2024                   Douglas            NE   Trained Spotter

            Low lying roadways are water-covered . Water
            is not up to the top of the gutters, but
            some vehicles are having difficulty driving
            through.

&&

tsn

Local storm report, May 21, 12:44 AM CDT, 9 minutes before

Preliminary Local Storm Report
National Weather Service Omaha/Valley NE
1244 AM CDT Tue May 21 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1235 AM     Rain             4 NNW Omaha             41.31N 96.05W
05/21/2024  M3.56 Inch       Douglas            NE   Mesonet

            Mesonet station IRVN1 3.7 NW Omaha.

1220 AM     Rain             4 NNE Boys Town         41.31N 96.10W
05/21/2024  M3.44 Inch       Douglas            NE   Mesonet

            Mesonet station OHAN1 3.6 NE Boys Town.

1200 AM     Rain             2 SSE Kennard           41.45N 96.19W
05/21/2024  M3.40 Inch       Washington         NE   Mesonet

            Mesonet station KEBN1 1.7 SE Kennard.

&&

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 7:35 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Saunders, Seward	40 min
May 20, 7:56 PM CDT	Severe Thunderstorm Warning	OAX	Lancaster, Saunders	45 min
May 20, 8:14 PM CDT	Severe Thunderstorm Warning	OAX	Knox	46 min
May 20, 8:51 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Knox	39 min
May 20, 8:57 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Saunders	63 min
May 20, 9:08 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Washington	52 min
May 20, 9:24 PM CDT	Severe Thunderstorm Warning	OAX	Cedar	51 min
May 20, 9:53 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Saunders, Seward	67 min
May 20, 10:06 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston	39 min
May 20, 10:17 PM CDT	Areal Flood Advisory	OAX	Butler, Saunders	9 hr
May 20, 10:28 PM CDT	Areal Flood Advisory	OAX	Butler, Lancaster, Saunders, Seward	2 hr
May 20, 10:54 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Sarpy, Saunders	66 min
May 20, 11:09 PM CDT	Severe Thunderstorm Warning	OAX	Cedar	36 min
May 20, 11:12 PM CDT	Flash Flood Warning	OAX	Douglas, Sarpy	3 hr
May 20, 11:14 PM CDT	Tornado Warning	OAX	Washington	28 min
May 20, 11:23 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Douglas, Sarpy, Washington	67 min
May 20, 11:49 PM CDT	Areal Flood Advisory	OAX	Washington	93 min
May 21, 12:45 AM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Dodge, Saunders	22 min
May 21, 1:35 AM CDT	Severe Thunderstorm Warning	OAX	Burt, Dodge, Washington	24 min
May 21, 2:38 AM CDT	Flash Flood Warning	OAX	Burt, Washington	5 hr
May 21, 2:54 AM CDT	Flash Flood Warning	OAX	Dodge	4 hr
May 21, 4:19 AM CDT	Areal Flood Advisory	OAX	Butler, Colfax, Dodge, Saunders	3 hr
May 21, 4:31 AM CDT	Severe Thunderstorm Warning	OAX	Boone, Butler, Madison, Platte, Stanton	44 min
May 21, 4:39 AM CDT	River Flood Warning	OAX	Saunders	40 hr
May 21, 4:42 AM CDT	Severe Thunderstorm Warning	OAX	Saunders	48 min
May 21, 4:43 AM CDT	Flash Flood Warning	OAX	Butler, Saunders	5 hr
May 21, 4:47 AM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone, Madison, Pierce, Platte	28 min
May 21, 5:00 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Butler, Colfax, Cuming, Dodge, Platte, Saunders	45 min
May 21, 5:02 AM CDT	River Flood Warning	OAX	Saunders	37 hr
May 21, 5:03 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Butler, Lancaster, Saline, Saunders, Seward	42 min
May 21, 5:10 AM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Madison, Platte, Stanton, Wayne	50 min
May 21, 5:12 AM CDT	Severe Thunderstorm Warning	OAX	Dodge, Douglas, Saunders, Washington	48 min
May 21, 5:12 AM CDT	Tornado Warning	OAX	Colfax, Dodge, Platte	33 min
May 21, 5:21 AM CDT	Flash Flood Warning	OAX	Dodge, Douglas, Sarpy, Washington	4 hr
May 21, 5:27 AM CDT	Tornado Warning	OAX	Butler, Colfax, Dodge, Saunders	33 min
May 21, 5:29 AM CDT	Areal Flood Advisory	OAX	Dodge, Douglas, Saunders, Washington	2 hr
May 21, 5:29 AM CDT	Tornado Warning	OAX	Butler, Saunders	31 min
May 21, 5:39 AM CDT	Tornado Warning	OAX	Burt, Cuming, Dodge, Washington	36 min
May 21, 5:41 AM CDT	Severe Thunderstorm Warning Destructive damage threat	OAX	Burt, Cuming, Dodge, Thurston, Washington	49 min
May 21, 5:44 AM CDT	Tornado Warning	OAX	Saunders	7 min
May 21, 5:45 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Dodge, Douglas, Sarpy, Saunders, Washington	45 min
May 21, 5:46 AM CDT	Areal Flood Advisory	OAX	Burt, Dodge, Douglas, Saunders, Washington	113 min
May 21, 5:49 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Cuming, Thurston, Wayne	41 min
May 21, 5:53 AM CDT	Severe Thunderstorm Warning	OAX	Douglas, Washington	52 min
May 21, 5:53 AM CDT	Tornado Warning	OAX	Dodge, Douglas, Saunders, Washington	37 min
May 21, 6:15 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Cass, Douglas, Sarpy, Washington	45 min
May 21, 6:50 AM CDT	Severe Thunderstorm Warning	OAX	Nemaha, Otoe	14 min
May 21, 6:56 AM CDT	Areal Flood Warning	OAX	Dodge	5 hr
May 21, 7:11 AM CDT	Flash Flood Warning	OAX	Washington	4 hr
May 21, 7:33 AM CDT	Areal Flood Warning	OAX	Burt, Butler, Colfax, Dodge, Douglas, Saunders and 1 more	10 hr
May 21, 8:29 AM CDT	River Flood Warning	OAX	Dodge	6 hr
May 21, 9:20 AM CDT	Areal Flood Warning	OAX	Douglas, Sarpy, Washington	8 hr
May 21, 10:03 AM CDT	River Flood Warning	OAX	Cass	55 hr
May 21, 10:03 AM CDT	River Flood Warning	OAX	Otoe	57 hr
May 21, 10:03 AM CDT	River Flood Warning	OAX	Nemaha	4 days
May 21, 10:03 AM CDT	River Flood Warning	OAX	Seward	33 hr
May 21, 11:20 AM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Seward	40 min
May 21, 11:48 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Butler, Lancaster, Saunders, Seward	42 min
May 21, 12:16 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Burt, Dodge, Douglas, Saunders, Washington	44 min
May 21, 12:38 PM CDT	Severe Thunderstorm Warning	OAX	Dodge, Douglas, Saunders, Washington	52 min
May 21, 12:44 PM CDT	Tornado Warning	OAX	Douglas, Saunders	31 min
May 21, 12:45 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Johnson, Otoe	45 min
May 21, 12:50 PM CDT	Tornado Warning	OAX	Dodge, Washington	19 min
May 21, 12:59 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Burt, Washington	61 min
May 21, 1:01 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Sarpy	59 min
May 21, 1:15 PM CDT	Tornado Warning	OAX	Cass, Otoe	45 min
May 21, 1:16 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Washington	59 min
May 21, 1:34 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Sarpy	26 min
May 21, 1:43 PM CDT	Tornado Warning	OAX	Cass, Otoe	47 min
May 21, 5:37 PM CDT	Areal Flood Warning	OAX	Butler, Dodge, Douglas, Saunders, Washington	15 hr
May 20, 8:37 PM CDT	Severe Thunderstorm Warning	OAX	Shelby	68 min
May 20, 9:42 PM CDT	Severe Thunderstorm Warning	OAX	Shelby	48 min
May 20, 9:51 PM CDT	Flash Flood Warning	OAX	Shelby	5 hr
May 20, 11:35 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Harrison, Pottawattamie, Shelby	40 min
May 21, 12:02 AM CDT	Tornado Warning	OAX	Harrison, Pottawattamie	43 min
May 21, 12:14 AM CDT	Severe Thunderstorm Warning	OAX	Harrison, Pottawattamie, Shelby	46 min
May 21, 12:42 AM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie, Shelby	63 min
May 21, 1:10 AM CDT	Tornado Warning	OAX	Shelby	25 min
May 21, 1:44 AM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie, Shelby	61 min
May 21, 6:11 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Harrison, Monona, Shelby	49 min

Nearby

Tornado Warnings in Iowa, 2024 Every tornado warning in 2024 Tornadoes in 2024

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.