Alert archive / Iowa / Flash Flood Warnings in 2019

Flash Flood Warning 9, NWS Sioux Falls, SD

July 1, 20194 counties in Iowa; Dakota County, Dixon County, Nebraska; Union County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at Jul 1, 2019, 9:28 PM CDT for 4 counties in Iowa; Dakota County, Dixon County, Nebraska; Union County, South Dakota. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 1, 2019, 9:28 PM CDT (02:28 UTC)
Expired
Jul 2, 2019, 12:30 AM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

Counties Cherokee County, IA, Ida County, IA, Plymouth County, IA, Woodbury County, IA, Dakota County, NE, Dixon County, NE, Union County, SD

The radar

The Omaha radar (KOAX), 118 km from the middle of the area, began a volume at 02:29 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.

What was reported inside it

TimeReportWhereRemark
Jul 1, 10:17 PM CDTFLASH FLOOD2 Wnw Sioux City, IASIOUX CITY POLICE ADVISED STREET FLOODING ON 19TH STREET BETWEEN ROSS AND CENTER STREET. MULTIPLE CARS STALLED IN STREET FLOODING ON FLOYD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.5 hours before the alert went out and 118 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-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2019-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1037 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2019-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1037 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
1798 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

297 
WGUS53 KFSD 020228
FFWFSD
IAC035-093-149-193-NEC043-051-SDC127-020530-
/O.NEW.KFSD.FF.W.0009.190702T0228Z-190702T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
928 PM CDT Mon Jul 1 2019

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Southern Cherokee County in northwestern Iowa...
  Woodbury County in west central Iowa...
  Southern Plymouth County in northwestern Iowa...
  Western Ida County in west central Iowa...
  Dakota County in northeastern Nebraska...
  Dixon County in northeastern Nebraska...
  Southern Union County in southeastern South Dakota...

* Until 1230 AM CDT.

* At 927 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to
  begin shortly.

* Some locations that will experience flooding include...
  Sioux City, Ponca, South Sioux City, Sergeant Bluff, North Sioux
  City, Elk Point, Dakota City, Moville, Wakefield, Kingsley, Sloan,
  Hinton, Lawton, Emerson, Correctionville, Anthon, Homer, Jefferson,
  Allen and Pierson.

Additional rainfall amounts of one to three inches are possible in 
the warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4222 9633 4225 9633 4228 9635 4227 9701
      4261 9701 4271 9662 4268 9549 4221 9568

$$

Weisser
1 follow-up statement
424 
WGUS73 KFSD 020341
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
1041 PM CDT Mon Jul 1 2019

IAC035-093-149-193-NEC043-051-SDC127-020530-
/O.CON.KFSD.FF.W.0009.000000T0000Z-190702T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cherokee IA-Woodbury IA-Plymouth IA-Ida IA-Dakota NE-Dixon NE-
Union SD-
1041 PM CDT Mon Jul 1 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT FOR
SOUTHERN CHEROKEE...WOODBURY...SOUTHERN PLYMOUTH...WESTERN IDA...
DAKOTA...DIXON AND SOUTHERN UNION COUNTIES...

At 1040 PM CDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Two to three inches of rain has 
already fallen. Flash flooding is expected to begin shortly.

Some locations that will experience flooding include...
Sioux City, Ponca, South Sioux City, Sergeant Bluff, North Sioux
City, Elk Point, Dakota City, Moville, Wakefield, Kingsley, Sloan,
Hinton, Lawton, Emerson, Correctionville, Anthon, Homer, Jefferson,
Allen and Pierson.

Additional rainfall amounts of one to three inches are possible in 
the warned area.

At 1017 pm CDT...street flooding was reported in downtown Sioux City 
with multiple stalled cars.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4222 9633 4225 9633 4228 9635 4227 9701
      4261 9701 4271 9662 4268 9549 4221 9568

$$

Weisser

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 1, 7:16 PM CDTFlash Flood WarningFSDSioux3 hr
Jul 1, 7:33 PM CDTFlash Flood WarningFSDO'Brien2 hr
Jul 1, 8:17 PM CDTFlash Flood WarningFSDCherokee, Plymouth, Sioux3 hr
Jul 1, 11:01 PM CDTRiver Flood WarningFSDLyon3 days
Jul 1, 11:01 PM CDTRiver Flood WarningFSDSioux21 days
Jul 1, 11:01 PM CDTRiver Flood WarningFSDSioux22 hr
Jul 2, 3:46 AM CDTRiver Flood WarningFSDPlymouth, Sioux48 hr
Jul 2, 7:40 AM CDTRiver Flood WarningFSDPlymouth, Sioux7 days
Jul 2, 10:04 AM CDTRiver Flood WarningFSDBrookings, Moody34 days

Nearby

Flash Flood Warnings in Iowa, 2019Flash Flood Warnings in Nebraska, 2019Flash Flood Warnings in South Dakota, 2019Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.