Alert archive / Iowa / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 239, NWS Omaha, NE

July 17, 2023Harrison County, Pottawattamie County, Shelby County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jul 17, 2023, 1:40 AM CDT for Harrison County, Pottawattamie County, Shelby County, Iowa. It was in force for 50 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: Jul 17, 2023, 1:40 AM CDT (06:40 UTC)
Expired: Jul 17, 2023, 2:30 AM CDT
In force: 50 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Harrison County, IA, Pottawattamie County, IA, Shelby County, IA

The radar

The Omaha radar (KOAX), 73 km from the middle of the area, began a volume at 06:40 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 00:00Z, 6.7 hours before the alert went out and 73 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: 1519 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 1326 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 16, 11:34 PM CDT, 2 hours 6 minutes earlier.

Area forecast discussion, Jul 16, 11:34 PM CDT, 2 hours 6 minutes before

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Hazardous weather outlook, Jul 16, 10:31 PM CDT, 3 hours 9 minutes before

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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 5:00 AM CDT	Special Weather Statement	OAX	Burt, Washington	30 min
Jul 17, 5:11 AM CDT	Severe Thunderstorm Warning	OAX	Burt, Washington	26 min
Jul 17, 6:08 AM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone	37 min
Jul 17, 6:21 AM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone, Madison	24 min
Jul 17, 6:34 AM CDT	Severe Thunderstorm Warning	OAX	Boone, Platte	21 min
Jul 17, 6:38 AM CDT	Severe Thunderstorm Warning	OAX	Madison, Platte, Stanton	37 min
Jul 17, 6:59 AM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge, Platte, Stanton	31 min
Jul 17, 7:19 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Colfax, Dodge, Washington	41 min
Jul 17, 7:48 AM CDT	Severe Thunderstorm Warning	OAX	Douglas	27 min
Jul 17, 7:55 AM CDT	Severe Thunderstorm Warning	OAX	Dodge, Douglas, Washington	50 min
Jul 17, 5:15 AM CDT	Severe Thunderstorm Warning	OAX	Harrison, Monona, Pottawattamie, Shelby	32 min
Jul 17, 7:14 AM CDT	Severe Thunderstorm Warning	OAX	Harrison, Shelby	18 min
Jul 17, 8:28 AM CDT	Severe Thunderstorm Warning	OAX	Mills	32 min
Jul 17, 8:37 AM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie	17 min
Jul 17, 8:42 AM CDT	Severe Thunderstorm Warning Considerable damage threat	OAX	Fremont, Montgomery, Page	48 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2023 Every severe thunderstorm warning in 2023

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.