Alert archive / Minnesota / Flash Flood Warnings in 2018

Flash Flood Warning 1, NWS Sioux Falls, SD

May 23, 2018Cottonwood County, Minnesota

NWS Sioux Falls, SD issued this flash flood warning at May 23, 2018, 3:20 AM CDT for Cottonwood County, Minnesota. 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 outline as issued.

The facts

Issued
May 23, 2018, 3:20 AM CDT (08:20 UTC)
Expired
May 23, 2018, 6:15 AM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

County Cottonwood County, MN

The radar

The Sioux Falls radar (KFSD), 134 km from the middle of the area, began a volume at 08:22 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

Minneapolis, MN (KMPX), launched 00:00Z, 8.3 hours before the alert went out and 159 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, Minneapolis, MN at 00:00Z on 2018-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2018-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1364 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
107 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

779 
WGUS53 KFSD 230820
FFWFSD
MNC033-231115-
/O.NEW.KFSD.FF.W.0001.180523T0820Z-180523T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
320 AM CDT WED MAY 23 2018

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  South central Cottonwood County in southwestern Minnesota...

* Until 615 AM CDT.

* At 317 AM 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...
  Areas near Windom and Bingham Lake. 

Areas north and west of Windom will likely see the greatest runoff 
and potential for flash flooding, especially with additional 
scattered storms forming to the west which will move across the
area through around 5 am. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4395 9502 4386 9504 4388 9530 4399 9527

$$

Chapman
2 follow-up statements
257 
WGUS73 KFSD 230937
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
437 AM CDT WED MAY 23 2018

MNC033-231115-
/O.CON.KFSD.FF.W.0001.000000T0000Z-180523T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cottonwood MN-
437 AM CDT WED MAY 23 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 AM CDT FOR
SOUTH CENTRAL COTTONWOOD COUNTY...

At 436 AM CDT, Doppler radar indicated heavy rain across the warned 
area.  Flash flooding, if not already underway, is expected to begin 
shortly.

Some locations that will experience flooding include...
Areas north of Windom and Bingham Lake. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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, country roads, farmland, and 
other low lying spots.

&&

LAT...LON 4395 9502 4386 9504 4388 9530 4399 9527

$$

Chapman
748 
WGUS73 KFSD 231118
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
618 AM CDT WED MAY 23 2018

MNC033-231122-
/O.EXP.KFSD.FF.W.0001.000000T0000Z-180523T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cottonwood MN-
618 AM CDT WED MAY 23 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL COTTONWOOD COUNTY WILL
EXPIRE AT 615 AM CDT...

The heavy rain has ended, and runoff from the earlier rainfall from 
an estimated 3 to 4 inches rainfall has likely ended. Flooding is no 
longer expected to pose a significant threat, but please continue to 
heed any remaining road closures if water remains over any roadways.

LAT...LON 4395 9502 4386 9504 4388 9530 4399 9527

$$

Chapman

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 1:19 AM CDTSevere Thunderstorm WarningFSDCottonwood, Jackson26 min
May 23, 2:34 AM CDTSevere Thunderstorm WarningFSDLyon, Murray12 min

Nearby

Flash Flood Warnings in Minnesota, 2018Every flash flood warning in 2018

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.