Alert archive / Nebraska / Flash Flood Warnings in 2019

Flash Flood Warning 46, NWS Omaha, NE

September 19, 2019Douglas County, Sarpy County, Saunders County, Nebraska; Mills County, Pottawattamie County, Iowa

NWS Omaha, NE issued this flash flood warning at Sep 19, 2019, 6:56 AM CDT for Douglas County, Sarpy County, Saunders County, Nebraska; Mills County, Pottawattamie County, Iowa. It was in force for 4 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: Sep 19, 2019, 6:56 AM CDT (11:56 UTC)
Expired: Sep 19, 2019, 11:00 AM CDT
In force: 4 hr
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Flood severity: None

Counties Mills County, IA, Pottawattamie County, IA, Douglas County, NE, Sarpy County, NE, Saunders County, NE

The radar

The Omaha radar (KOAX), 32 km from the middle of the area, began a volume at 11:59 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, 11.9 hours before the alert went out and 33 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: 2448 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1305 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 187 m²/s²
0-3 km storm-relative helicity: 381 m²/s²
Significant tornado parameter: 2.3
Supercell composite: 8.8

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 Sep 19, 6:18 AM CDT, 38 minutes earlier.

Area forecast discussion, Sep 19, 6:18 AM CDT, 38 minutes before

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Hazardous weather outlook, Sep 19, 4:06 AM CDT, 2 hours 50 minutes before

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In the hours before

Special weather statement, Sep 19, 1:11 AM CDT, 5 hours 45 minutes before

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
111 AM CDT Thu Sep 19 2019

IAZ043-NEZ015-017-018-030>034-190700-
Monona IA-Stanton NE-Thurston NE-Madison NE-Burt NE-Pierce NE-
Boone NE-Cuming NE-Wayne NE-
111 AM CDT Thu Sep 19 2019

...SIGNIFICANT WEATHER ADVISORY FOR MONONA...NORTHERN MADISON...
NORTHERN BURT...WAYNE...NORTHERN CUMING...SOUTHERN PIERCE...
THURSTON...NORTHEASTERN BOONE AND NORTHERN STANTON COUNTIES UNTIL 200
AM CDT...

At 110 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 4 miles north of Elgin to 4 miles northeast of
Pilger to near Moorhead. Movement was northeast at 15 mph.

Very heavy rainfall, penny size hail and winds in excess of 30 mph
will be possible with these storms.

Locations impacted include...
Norfolk, Wayne, Onawa, Pierce, Stanton, Wakefield, Battle Creek,
Wisner, Pender, Lyons, Walthill, Winnebago, Whiting, Beemer,
Bancroft, Decatur, Winside, Ute, Pilger and Meadow Grove.

This includes Interstate 29 between mile markers 101 and 125.

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.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4192 9783 4214 9784 4221 9779 4231 9715
      4231 9702 4226 9701 4227 9635 4222 9633
      4221 9608 4211 9567 4191 9567 4186 9581
      4191 9670 4188 9737 4190 9800
TIME...MOT...LOC 0610Z 241DEG 15KT 4205 9807 4207 9702 4190 9588

KG

Local storm report, Sep 19, 1:52 AM CDT, 5 hours 4 minutes before

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Local storm report, Sep 19, 2:21 AM CDT, 4 hours 35 minutes before

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Special weather statement, Sep 19, 4:47 AM CDT, 2 hours 9 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, 7:06 PM CDT	Special Weather Statement	OAX	Cass	24 min
Sep 18, 7:34 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster, Otoe, Saunders	26 min
Sep 18, 8:04 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster	20 min
Sep 18, 9:12 PM CDT	Special Weather Statement	OAX	Dodge	33 min
Sep 18, 9:15 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge	30 min
Sep 18, 9:58 PM CDT	Flash Flood Warning	OAX	Colfax, Cuming, Dodge	3 hr
Sep 18, 10:47 PM CDT	Special Weather Statement	OAX	Cuming	28 min
Sep 19, 12:29 AM CDT	Flash Flood Warning	OAX	Burt, Cuming, Stanton, Thurston, Wayne	10 hr
Sep 19, 1:11 AM CDT	Special Weather Statement	OAX	Cuming, Madison, Stanton, Thurston, Wayne	49 min
Sep 19, 2:40 AM CDT	Flash Flood Warning	OAX	Pierce, Stanton, Wayne	6 hr
Sep 19, 2:46 AM CDT	Flash Flood Warning	OAX	Burt, Thurston	6 hr
Sep 19, 4:00 AM CDT	Flash Flood Warning	OAX	Cuming, Thurston	5 hr
Sep 19, 4:05 AM CDT	Flash Flood Warning	OAX	Cedar, Pierce, Wayne	5 hr
Sep 19, 4:47 AM CDT	Special Weather Statement	OAX	Burt, Douglas, Sarpy, Washington	43 min
Sep 19, 5:06 AM CDT	Flash Flood Warning	OAX	Burt, Douglas, Washington	6 hr
Sep 19, 5:52 AM CDT	Areal Flood Advisory	OAX	Douglas, Sarpy	3 hr
Sep 19, 9:37 AM CDT	Areal Flood Warning	OAX	Burt, Cedar, Colfax, Cuming, Dodge, Douglas and 6 more	6 hr
Sep 19, 11:02 AM CDT	Areal Flood Warning	OAX	Douglas, Sarpy	5 hr

Nearby

Flash Flood Warnings in Nebraska, 2019 Flash Flood Warnings in Iowa, 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.