Alert archive / Nebraska / Flash Flood Warnings in 1999

Flash Flood Warning 13, NWS Sioux Falls, SD

July 18, 1999Dakota County, Nebraska

NWS Sioux Falls, SD issued this flash flood warning at Jul 18, 1999, 3:21 AM CDT for Dakota County, Nebraska. 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 counties it named.

The facts

Issued
Jul 18, 1999, 3:21 AM CDT (08:21 UTC)
Expired
Jul 18, 1999, 6:20 AM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Dakota County, NE

The radar

The Omaha radar (KOAX), 120 km from the middle of the area, began a volume at 08:20 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, 8.4 hours before the alert went out and 120 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 1999-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 452 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 1999-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 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
452 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
765 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
273 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 180830 COR
FFWFSD
IAC021-035-093-193-NEC043-181120-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
URBAN FLOOD WARNING...CORRECTION TO MOVEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
321 AM CDT SUN JUL 18 1999

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* URBAN FLOOD WARNING FOR...
  BUENA VISTA COUNTY IN NORTHWESTERN IOWA
  CHEROKEE COUNTY IN NORTHWESTERN IOWA
  IDA COUNTY IN NORTHWESTERN IOWA
  WOODBURY COUNTY IN NORTHWESTERN IOWA
  DAKOTA COUNTY IN NORTHEASTERN NEBRASKA

* UNTIL 620 AM CDT

* AT 315 AM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN AROUND SIOUX CITY...MOVING SLOWLY NORTHEAST.

RAINFALL AMOUNTS WILL RANGE FROM AN INCH TO TWO INCHES IN A
HOUR.p..SO LOCALIZED URBAN FLOODING IS LIKELY.  DAKOTA COUNTY
EMERGENCY MANAGEMENT REPORTED SOME HOMES IN SOUTH SIOUX CITY WERE
FLOODED.  MANY OF THESE HOMES WERE HIT HARD A WEEK AGO.

DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

HEITKAMP

Nearby

Flash Flood Warnings in Nebraska, 1999Every flash flood warning in 1999

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.