Alert archive / Nebraska / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 277, NWS Omaha, NE

September 18, 2018Cass County, Otoe County, Nebraska; Fremont County, Mills County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Sep 18, 2018, 4:49 PM CDT for Cass County, Otoe County, Nebraska; Fremont County, Mills County, Iowa. It was in force for 41 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: Sep 18, 2018, 4:49 PM CDT (21:49 UTC)
Expired: Sep 18, 2018, 5:30 PM CDT
In force: 41 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

Counties Fremont County, IA, Mills County, IA, Cass County, NE, Otoe County, NE

The radar

The Omaha radar (KOAX), 68 km from the middle of the area, began a volume at 21:52 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, 9.8 hours before the alert went out and 68 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: 1380 J/kg
Mixed-layer CIN: -109 J/kg
Mixed-layer LCL: 1445 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: -25 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Sep 18, 3:28 PM CDT, 1 hour 21 minutes earlier.

Area forecast discussion, Sep 18, 3:28 PM CDT, 1 hour 21 minutes before

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Hazardous weather outlook, Sep 18, 4:39 PM CDT, 10 minutes before

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In the hours before

Local storm report, Sep 18, 3:38 PM CDT, 1 hour 11 minutes before

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Special weather statement, Sep 18, 4:00 PM CDT, 49 minutes before

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Special weather statement, Sep 18, 4:04 PM CDT, 45 minutes before

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Local storm report, Sep 18, 4:06 PM CDT, 43 minutes before

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Local storm report, Sep 18, 4:07 PM CDT, 42 minutes before

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Local storm report, Sep 18, 4:42 PM CDT, 7 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 2:29 PM CDT	Special Weather Statement	OAX	Dodge	46 min
Sep 18, 2:54 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	36 min
Sep 18, 3:22 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	38 min
Sep 18, 3:55 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Sarpy, Saunders	35 min
Sep 18, 4:00 PM CDT	Special Weather Statement	OAX	Otoe	30 min
Sep 18, 4:04 PM CDT	Special Weather Statement	OAX	Lancaster	56 min
Sep 18, 4:08 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster, Sarpy, Saunders	52 min
Sep 18, 4:13 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Lancaster, Otoe	32 min
Sep 18, 4:25 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Sarpy	50 min
Sep 18, 4:35 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster, Otoe	40 min
Sep 18, 11:28 AM CDT	Special Weather Statement	OAX	Monona	32 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2018 Severe Thunderstorm Warnings in Iowa, 2018 Every severe thunderstorm warning in 2018

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.