Alert archive / South Dakota / Flash Flood Warnings in 2018

Flash Flood Warning 40, NWS Sioux Falls, SD

September 20, 2018Hutchinson County, Turner County, Yankton County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at Sep 20, 2018, 4:51 AM CDT for Hutchinson County, Turner County, Yankton County, South Dakota. It was in force for 5 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
Sep 20, 2018, 4:51 AM CDT (09:51 UTC)
Expired
Sep 20, 2018, 9:45 AM CDT
In force
5 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

Counties Hutchinson County, SD, Turner County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 66 km from the middle of the area, began a volume at 09:53 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
Sep 20, 7:35 AM CDTFLASH FLOODLesterville, SDCOUNTY OFFICIALS ARE CLOSING ROADS IN NORTHERN PARTS OF YANKTON COUNTRY, WORRIED ABOUT ROADS WASHING OUT.
Sep 20, 7:55 AM CDTFLASH FLOOD4 Sse Olivet, SDWATER ACROSS NUMEROUS ROADS.
Sep 20, 9:02 AM CDTHEAVY RAIN 5.510 Wsw Hurley, SDREPORT VIA SOCIAL MEDIA. RAINFALL FOR PAST 2 DAYS AT TURKEY RIDGE SD.

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

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 9.9 hours before the alert went out and 203 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, Aberdeen, SD at 00:00Z on 2018-09-20Temperature 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, Aberdeen, SD at 00:00Z on 2018-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 square meters per square second.1939587897Sfc1 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
645 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

556 
WGUS53 KFSD 200951
FFWFSD
SDC067-125-135-201445-
/O.NEW.KFSD.FF.W.0040.180920T0951Z-180920T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
451 AM CDT THU SEP 20 2018

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Yankton County in southeastern South Dakota...
  Northwestern Turner County in southeastern South Dakota...
  Hutchinson County in southeastern South Dakota...

* Until 945 AM CDT.

* At 448 AM CDT, emergency management reported multiple roads with 
  water flowing over roads. One and a half to two and a half inches 
  of rain has already fallen on saturated ground overnight, with 
  additional rain through the morning hours. Flash flooding is 
  occurring and will likely continue for the next several hours.

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.

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

&&

LAT...LON 4317 9764 4317 9787 4350 9787 4350 9740
      4344 9692 4334 9693 4328 9719 4323 9726
      4317 9722 4317 9716 4291 9716 4291 9764

$$

VandenBoogart

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 3:36 AM CDTFlash Flood WarningFSDClay, Lincoln, Turner6 hr
Sep 20, 4:35 AM CDTFlash Flood WarningFSDClay, Lincoln, Union5 hr
Sep 20, 6:49 AM CDTRiver Flood WarningFSDBrookings, Moody5 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDMinnehaha, Moody4 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDMinnehaha3 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDLincoln, Minnehaha51 hr
Sep 20, 6:49 AM CDTRiver Flood WarningFSDUnion10 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDUnion12 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDHutchinson, Yankton6 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDYankton7 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDTurner7 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDClay7 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDMinnehaha4 days
Sep 20, 6:49 AM CDTRiver Flood WarningFSDMinnehaha63 hr
Sep 20, 7:22 AM CDTRiver Flood WarningFSDLincoln, Minnehaha63 hr
Sep 20, 9:15 AM CDTRiver Flood WarningFSDMinnehaha6 days
Sep 20, 9:29 AM CDTFlash Flood WarningFSDClay, Lincoln, Turner3 hr
Sep 20, 9:30 AM CDTFlash Flood WarningFSDClay, Lincoln, Union3 hr
Sep 20, 9:36 AM CDTRiver Flood WarningFSDClay8 days
Sep 20, 9:41 AM CDTFlash Flood WarningFSDHutchinson, Turner, Yankton3 hr
Sep 20, 11:17 AM CDTRiver Flood WarningFSDMinnehaha6 days
Sep 20, 12:39 PM CDTAreal Flood WarningFSDClay, Hutchinson, Lincoln, Turner, Union, Yankton12 hr
Sep 20, 2:44 PM CDTRiver Flood WarningFSDLincoln5 days
Sep 20, 3:32 PM CDTSevere Thunderstorm WarningFSDLincoln, Minnehaha43 min
Sep 20, 3:59 PM CDTSevere Thunderstorm WarningFSDUnion46 min
Sep 20, 4:17 PM CDTTornado WarningFSDUnion28 min

Nearby

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