Alert archive / Iowa / Flash Flood Warnings in 2015

Flash Flood Warning 9, NWS Sioux Falls, SD

August 16, 2015Woodbury County, Iowa; Dakota County, Nebraska

NWS Sioux Falls, SD issued this flash flood warning at Aug 16, 2015, 7:10 PM CDT for Woodbury County, Iowa; Dakota County, Nebraska. It was in force for 3 hr. 3 reports 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: Aug 16, 2015, 7:10 PM CDT (00:10 UTC)
Expired: Aug 16, 2015, 10:15 PM CDT
In force: 3 hr
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Flood severity: None

Counties Woodbury County, IA, Dakota County, NE

The radar

The Omaha radar (KOAX), 125 km from the middle of the area, began a volume at 00:12 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

Time	Report	Where	Remark
Aug 16, 7:35 PM CDT	FLASH FLOOD	Sioux City, IA	MANHOLE COVERS POPPING OFF DUE TO HEAVY RAINFALL AROUND PARTS OF THE CITY.
Aug 16, 7:40 PM CDT	FLASH FLOOD	Sioux City, IA	STREET FLOODING WITH STANDING WATER 2 FEET DEEP IN CENTRAL PARTS OF THE CITY.
Aug 16, 7:45 PM CDT	HEAVY RAIN 2.2	Sioux City, IA

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, 0.2 hours before the alert went out and 125 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: 344 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 1572 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 112 m²/s²
0-3 km storm-relative helicity: 176 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

753 
WGUS53 KFSD 170010
FFWFSD
IAC193-NEC043-170315-
/O.NEW.KFSD.FF.W.0009.150817T0010Z-150817T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
710 PM CDT SUN AUG 16 2015

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN WOODBURY COUNTY IN WEST CENTRAL IOWA...
  EASTERN DAKOTA COUNTY IN NORTHEASTERN NEBRASKA...

* UNTIL 1015 PM CDT
    
* AT 710 PM CDT...DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. FLASH FLOODING IS EXPECTED TO
  BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  SIOUX CITY...SOUTH SIOUX CITY...SERGEANT BLUFF...DAKOTA CITY...
  HOMER...JACKSON IN DAKOTA COUNTY AND BRONSON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4247 9659 4248 9650 4248 9647 4249 9645
      4252 9627 4236 9616 4228 9656

$$

WEISSER

2 follow-up statements

096 
WGUS73 KFSD 170047
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
747 PM CDT SUN AUG 16 2015

IAC193-NEC043-170315-
/O.CON.KFSD.FF.W.0009.000000T0000Z-150817T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WOODBURY IA-DAKOTA NE-
747 PM CDT SUN AUG 16 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT FOR
NORTHWESTERN WOODBURY AND EASTERN DAKOTA COUNTIES...

AT 745 PM CDT...THE PUBLIC REPORTED HEAVY RAIN FROM THUNDERSTORMS IN 
SOUTH SIOUX CITY. 2.23 INCHES OF RAIN HAS ALREADY FALLEN IN ABOUT 1 
HOUR. FLASH FLOODING IS EXPECTED.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
SIOUX CITY...SOUTH SIOUX CITY...SERGEANT BLUFF...DAKOTA CITY...
HOMER...JACKSON IN DAKOTA COUNTY AND BRONSON.

ADDITIONAL RAINFALL AMOUNTS OF ABOUT AN INCH ARE POSSIBLE IN THE 
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4247 9659 4248 9650 4248 9647 4249 9645
      4252 9627 4236 9616 4228 9656

$$

WEISSER

631 
WGUS73 KFSD 170318
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1018 PM CDT SUN AUG 16 2015

IAC193-NEC043-170328-
/O.EXP.KFSD.FF.W.0009.000000T0000Z-150817T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WOODBURY IA-DAKOTA NE-
1018 PM CDT SUN AUG 16 2015

...THE FLASH FLOOD WARNING FOR NORTHWESTERN WOODBURY AND EASTERN
DAKOTA COUNTIES HAS EXPIRED...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO POSE
A THREAT.

ADDITIONAL HEAVY RAIN WILL AGAIN BE POSSIBLE MONDAY NIGHT INTO 
TUESDAY.

LAT...LON 4247 9659 4248 9650 4248 9647 4249 9645
      4252 9627 4236 9616 4228 9656

$$

WEISSER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 16, 11:37 PM CDT	Flash Flood Warning	FSD	Cherokee, Ida, Plymouth, Woodbury	3 hr
Aug 17, 6:28 AM CDT	Areal Flood Warning	FSD	Cherokee, Plymouth	48 hr
Aug 17, 4:47 PM CDT	River Flood Warning	FSD	Monona, Woodbury	59 hr

Nearby

Flash Flood Warnings in Iowa, 2015 Flash Flood Warnings in Nebraska, 2015 Every flash flood warning in 2015

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.