Alert archive / Nebraska / Flash Flood Warnings in 2019

Flash Flood Warning 37, NWS Omaha, NE

August 21, 20194 counties in Nebraska

NWS Omaha, NE issued this flash flood warning at Aug 21, 2019, 6:21 AM CDT for 4 counties in Nebraska. It was in force for 114 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: Aug 21, 2019, 6:21 AM CDT (11:21 UTC)
Expired: Aug 21, 2019, 8:15 AM CDT
In force: 114 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Flood severity: None

Counties Gage County, NE, Johnson County, NE, Pawnee County, NE, Richardson County, NE

The radar

The Omaha radar (KOAX), 122 km from the middle of the area, began a volume at 11:22 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

Topeka, KS (KTOP), launched 00:00Z, 11.4 hours before the alert went out and 146 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: 5140 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 1104 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 256 m²/s²
Significant tornado parameter: 3.0
Supercell composite: 22.9

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Aug 21, 6:02 AM CDT, 19 minutes earlier.

Area forecast discussion, Aug 21, 6:02 AM CDT, 19 minutes before

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Hazardous weather outlook, Aug 21, 4:17 AM CDT, 2 hours 4 minutes before

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In the hours before

Special weather statement, Aug 21, 2:21 AM CDT, 4 hours before

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Local storm report, Aug 21, 2:32 AM CDT, 3 hours 49 minutes before

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Special weather statement, Aug 21, 3:19 AM CDT, 3 hours 2 minutes before

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Local storm report, Aug 21, 3:43 AM CDT, 2 hours 38 minutes before

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Local storm report, Aug 21, 6:10 AM CDT, 11 minutes before

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Local storm report, Aug 21, 6:17 AM CDT, 4 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
Aug 21, 1:42 AM CDT	Special Weather Statement	OAX	Johnson, Nemaha	33 min
Aug 21, 1:45 AM CDT	Special Weather Statement	OAX	Jefferson	30 min
Aug 21, 1:50 AM CDT	Severe Thunderstorm Warning	OAX	Gage, Johnson, Pawnee	25 min
Aug 21, 2:21 AM CDT	Special Weather Statement	OAX	Gage, Pawnee	24 min
Aug 21, 2:25 AM CDT	Severe Thunderstorm Warning	OAX	Gage, Johnson, Pawnee, Richardson	24 min
Aug 21, 2:33 AM CDT	Flash Flood Warning	OAX	Johnson, Nemaha	6 hr
Aug 21, 2:37 AM CDT	Flash Flood Warning	OAX	Richardson	6 hr
Aug 21, 3:19 AM CDT	Special Weather Statement	OAX	Saline	26 min
Aug 21, 3:36 AM CDT	Flash Flood Warning	OAX	Gage, Johnson, Pawnee, Richardson	3 hr
Aug 21, 3:42 AM CDT	Severe Thunderstorm Warning	OAX	Saline, Seward	18 min

Nearby

Flash Flood Warnings in Nebraska, 2019 Every flash flood warning in 2019

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.