Alert archive / Nebraska / Flash Flood Warnings in 2019

Flash Flood Warning 36, NWS Omaha, NE

August 21, 20194 counties in Nebraska

NWS Omaha, NE issued this flash flood warning at Aug 21, 2019, 3:36 AM CDT for 4 counties in Nebraska. It was in force for 3 hr. 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, 3:36 AM CDT (08:36 UTC)
Expired: Aug 21, 2019, 6:30 AM CDT
In force: 3 hr
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 08:36 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, 8.6 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, 3:18 AM CDT, 18 minutes earlier.

Area forecast discussion, Aug 21, 3:18 AM CDT, 18 minutes before

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Hazardous weather outlook, Aug 20, 6:58 PM CDT, 8 hours 38 minutes before

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
658 PM CDT Tue Aug 20 2019

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-211400-
Monona-Harrison-Shelby-Pottawattamie-Mills-Montgomery-Fremont-
Page-Knox-Cedar-Thurston-Antelope-Pierce-Wayne-Boone-Madison-
Stanton-Cuming-Burt-Platte-Colfax-Dodge-Washington-Butler-
Saunders-Douglas-Sarpy-Seward-Lancaster-Cass-Otoe-Saline-
Jefferson-Gage-Johnson-Nemaha-Pawnee-Richardson-
658 PM CDT Tue Aug 20 2019

This Hazardous Weather Outlook is for portions of southwest
Iowa...west central Iowa...east central Nebraska...northeast
Nebraska and southeast Nebraska.

.DAY ONE...Tonight and Wednesday

Thunderstorms are expected to increase in coverage and intensity
across the area after midnight and linger into Wednesday morning.
The strongest storms will be capable hail to golf ball size,
damaging winds of 60 to 70 mph, and locally heavy rainfall. The
greatest severe weather threat will exist south of a Neligh to
Onawa, Iowa line.

Minor flooding will continue on the Missouri River above Lewis
and Clark Lake and from around Plattsmouth downstream past Rulo.

.DAYS TWO THROUGH SEVEN...Wednesday night through Tuesday

Rain and thunderstorms are expected to continue into Thursday. No
severe weather is anticipated.

Minor flooding will continue on the Missouri River above Lewis
and Clark Lake and from around Plattsmouth downstream into
Missouri.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will probably not be needed tonight.

In the hours before

Special weather statement, Aug 21, 1:42 AM CDT, 1 hour 54 minutes before

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
142 AM CDT Wed Aug 21 2019

NEZ066-089>093-210715-
Gage NE-Pawnee NE-Lancaster NE-Johnson NE-Nemaha NE-Richardson NE-
142 AM CDT Wed Aug 21 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LANCASTER...
JOHNSON...SOUTHWESTERN NEMAHA...NORTHWESTERN RICHARDSON...
NORTHEASTERN PAWNEE AND NORTHEASTERN GAGE COUNTIES UNTIL 215 AM
CDT...

At 142 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Cortland to 8 miles south of Sterling to 8
miles north of Humboldt. Movement was south at 10 mph.

Penny size hail and wind gusts up to 50 mph will be possible with
these storms.

Locations impacted include...
Auburn, Tecumseh, Firth, Cortland, Sterling, Johnson, Hallam,
Pickrell, Stella, Adams, Sprague, Elk Creek, Crab Orchard, 7 Miles
South Of Auburn, Stagecoach State Recreation Area and 8 Miles South
Of Johnson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4022 9621 4040 9680 4064 9677 4048 9633
      4041 9581 4019 9568
TIME...MOT...LOC 0642Z 339DEG 8KT 4048 9676 4034 9636 4028 9593

MEAD

Special weather statement, Aug 21, 1:45 AM CDT, 1 hour 51 minutes before

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
145 AM CDT Wed Aug 21 2019

NEZ078-088-089-210715-
Jefferson NE-Gage NE-Saline NE-
145 AM CDT Wed Aug 21 2019

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN JEFFERSON...
SOUTHEASTERN SALINE AND WEST CENTRAL GAGE COUNTIES UNTIL 215 AM
CDT...

At 145 AM CDT, Doppler radar was tracking a strong thunderstorm 5
miles northwest of Plymouth, or 17 miles west of Beatrice, moving
southeast at 15 mph.

Penny size hail will be possible with this storm.

Locations impacted include...
De Witt, Plymouth, Western, Jansen, Swanton, Harbine, Swan Creek
Wildlife Management Area and Cub Creek Recreational Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4031 9728 4047 9715 4036 9679 4010 9700
TIME...MOT...LOC 0645Z 301DEG 12KT 4034 9707

MEAD

Special weather statement, Aug 21, 2:21 AM CDT, 1 hour 15 minutes before

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Local storm report, Aug 21, 2:32 AM CDT, 1 hour 4 minutes before

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Special weather statement, Aug 21, 3:19 AM CDT, 17 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, 3:42 AM CDT	Severe Thunderstorm Warning	OAX	Saline, Seward	18 min
Aug 21, 6:21 AM CDT	Flash Flood Warning	OAX	Gage, Johnson, Pawnee, Richardson	114 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.