Alert archive / Iowa / Flash Flood Warnings in 2017

Flash Flood Warning 4, NWS Sioux Falls, SD

August 24, 2017Plymouth County, Iowa

NWS Sioux Falls, SD issued this flash flood warning at Aug 24, 2017, 8:21 PM CDT for Plymouth 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 outline as issued.

The facts

Issued
Aug 24, 2017, 8:21 PM CDT (01:21 UTC)
Expired
Aug 25, 2017, 12:15 AM CDT
In force
4 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

County Plymouth County, IA

The radar

The Sioux Falls radar (KFSD), 110 km from the middle of the area, began a volume at 01:23 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, 1.4 hours before the alert went out and 151 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 2017-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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 2017-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.19395878Sfc1 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
6 J/kg
Mixed-layer CIN
-329 J/kg
Mixed-layer LCL
1522 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

578 
WGUS53 KFSD 250121
FFWFSD
IAC149-250515-
/O.NEW.KFSD.FF.W.0004.170825T0121Z-170825T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
821 PM CDT THU AUG 24 2017

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Southeastern Plymouth County in northwestern Iowa...

* Until 1215 AM CDT

* At 820 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to three inches of rain have 
  already fallen. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Le Mars, Kingsley, Hinton and Merrill. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you
can do so safely.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4263 9642 4278 9639 4275 9592 4256 9599

$$

Dux
1 follow-up statement
144 
WGUS73 KFSD 250333
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
1033 PM CDT THU AUG 24 2017

IAC149-250515-
/O.CON.KFSD.FF.W.0004.000000T0000Z-170825T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Plymouth IA-
1033 PM CDT THU AUG 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM CDT FOR
SOUTHEASTERN PLYMOUTH COUNTY...

At 1032 PM CDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Up to three to four inches of 
rain have already fallen. Flash flooding and rapid rises in area 
creeks and streams is taking place.

Some locations that will experience flooding include...
Le Mars, Kingsley, Hinton and Merrill. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you
can do so safely.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4263 9642 4278 9639 4275 9592 4256 9599

$$

Dux

Nearby

Flash Flood Warnings in Iowa, 2017Every flash flood warning in 2017

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.