Alert archive / Nebraska / Flash Flood Warnings in 2018

Flash Flood Warning 37, NWS Sioux Falls, SD

September 18, 2018Dakota County, Dixon County, Nebraska; Woodbury County, Iowa

NWS Sioux Falls, SD issued this flash flood warning at Sep 18, 2018, 10:48 AM CDT for Dakota County, Dixon County, Nebraska; Woodbury County, Iowa. It was in force for 2 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
Sep 18, 2018, 10:48 AM CDT (15:48 UTC)
Expired
Sep 18, 2018, 12:58 PM CDT
In force
2 hr
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Flood severity
None

Counties Woodbury County, IA, Dakota County, NE, Dixon County, NE

The radar

The Omaha radar (KOAX), 107 km from the middle of the area, began a volume at 15:51 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 12:00Z, 3.8 hours before the alert went out and 107 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 12:00Z on 2018-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1380 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 12:00Z on 2018-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 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
1380 J/kg
Mixed-layer CIN
-109 J/kg
Mixed-layer LCL
1445 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
-25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

853 
WGUS53 KFSD 181548
FFWFSD
IAC193-NEC043-051-181845-
/O.NEW.KFSD.FF.W.0037.180918T1548Z-180918T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
1048 AM CDT TUE SEP 18 2018

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Southwestern Woodbury County in west central Iowa...
  Southern Dakota County in northeastern Nebraska...
  South central Dixon County in northeastern Nebraska...

* Until 145 PM CDT.

* At 1046 AM 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.

Additional rainfall amounts of 1 to 3 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.

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

&&

LAT...LON 4223 9633 4225 9633 4228 9635 4228 9672
      4227 9673 4227 9687 4236 9687 4245 9620
      4221 9621 4222 9634

$$

Gillispie
1 follow-up statement
430 
WGUS73 KFSD 181758
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
1258 PM CDT TUE SEP 18 2018

IAC193-NEC043-051-181806-
/O.CAN.KFSD.FF.W.0037.000000T0000Z-180918T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Woodbury IA-Dakota NE-Dixon NE-
1258 PM CDT TUE SEP 18 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN WOODBURY...SOUTHERN
DAKOTA AND SOUTH CENTRAL DIXON COUNTIES IS CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 4223 9633 4225 9633 4228 9635 4228 9672
      4227 9673 4227 9687 4236 9687 4245 9620
      4221 9621 4222 9634

$$

Gillispie

Nearby

Flash Flood Warnings in Nebraska, 2018Flash Flood Warnings in Iowa, 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.