Alert archive / South Dakota / Flash Flood Watches in 2015

Flash Flood Watch 6, NWS Sioux Falls, SD

September 23, 201510 counties in South Dakota; 5 counties in Iowa

NWS Sioux Falls, SD issued this flash flood watch at Sep 23, 2015, 4:14 AM CDT for 10 counties in South Dakota; 5 counties in Iowa. It took effect at Sep 23, 2015, 1:00 PM CDT. It was in force for 18 hr.

The area

The counties it named.

The facts

Issued: Sep 23, 2015, 4:14 AM CDT (09:14 UTC)
In effect from: Sep 23, 2015, 1:00 PM CDT
Expired: Sep 24, 2015, 6:46 AM CDT
In force: 18 hr
Issued by: NWS Sioux Falls, SD
Flood severity: None

Counties Cherokee County, IA, Ida County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Gregory County, SD, Hutchinson County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 73 km from the middle of the area, began a volume at 09:18 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, 9.2 hours before the alert went out and 194 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 504 J/kg
Mixed-layer CIN: -241 J/kg
Mixed-layer LCL: 1351 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: 370 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before this flash flood watch went out at Sep 23, 12:44 AM CDT, 3 hours 30 minutes earlier.

Area forecast discussion, Sep 23, 12:44 AM CDT, 3 hours 30 minutes before

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Hazardous weather outlook, Sep 22, 8:36 PM CDT, 7 hours 38 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
836 PM CDT TUE SEP 22 2015

IAZ001-012-020-031-MNZ071-097-098-NEZ013-014-SDZ038>040-050-
052>071-240145-
LYON IA-SIOUX-PLYMOUTH-WOODBURY-LINCOLN MN-PIPESTONE-ROCK-DIXON-
DAKOTA-BEADLE-KINGSBURY-BROOKINGS-GREGORY-JERAULD-SANBORN-MINER-
LAKE-MOODY-BRULE-AURORA-DAVISON-HANSON-MCCOOK-MINNEHAHA-
CHARLES MIX-DOUGLAS-HUTCHINSON-TURNER-LINCOLN SD-BON HOMME-
YANKTON-CLAY SD-UNION-
836 PM CDT TUE SEP 22 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
IOWA...SOUTHWEST MINNESOTA...NORTHEAST NEBRASKA...EAST CENTRAL
SOUTH DAKOTA...SOUTH CENTRAL SOUTH DAKOTA AND SOUTHEAST SOUTH
DAKOTA.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP TONIGHT AND
CONTINUE OVERNIGHT. A FEW STORMS MAY PRODUCE HAIL TO THE SIZE OF
HALF DOLLARS AND GUSTY WINDS TO 50 MPH.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME WIDESPREAD
WEDNESDAY AFTERNOON INTO THURSDAY...WITH LOCALLY HEAVY RAINFALL
POSSIBLE WEDNESDAY NIGHT. SEVERE WEATHER IS NOT EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE POSSIBLE AFTER 10 PM TONIGHT.

IAZ002-003-013-014-021-022-032-MNZ072-080-081-089-090-240145-
OSCEOLA-DICKINSON-O'BRIEN-CLAY IA-CHEROKEE-BUENA VISTA-IDA-
LYON MN-MURRAY-COTTONWOOD-NOBLES-JACKSON-
836 PM CDT TUE SEP 22 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST IOWA
AND SOUTHWEST MINNESOTA.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS EVENING AND
CONTINUE INTO THE OVERNIGHT HOURS. A FEW STORMS MAY PRODUCE HAIL
TO ONE INCH IN DIAMETER AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME WIDESPREAD
WEDNESDAY AFTERNOON INTO THURSDAY...WITH LOCALLY HEAVY RAINFALL
POSSIBLE WEDNESDAY NIGHT. SEVERE WEATHER IS NOT EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

In the hours before

Local storm report, Sep 23, 12:22 AM CDT, 3 hours 52 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1222 AM CDT WED SEP 23 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1214 AM     HEAVY RAIN       PICKSTOWN               43.07N 98.53W
09/23/2015  E3.50 INCH       CHARLES MIX        SD   PUBLIC

&&

NWS SIOUX FALLS SD
IRIS SYSTEM

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 22, 10:32 PM CDT	Flash Flood Warning	FSD	Gregory	2 hr
Sep 22, 10:37 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Gregory	23 min
Sep 22, 11:56 PM CDT	Flash Flood Warning	FSD	Charles Mix, Gregory	4 hr
Sep 23, 12:28 AM CDT	Flash Flood Warning	FSD	Bon Homme, Charles Mix	4 hr

Nearby

Flash Flood Watches in South Dakota, 2015 Flash Flood Watches in Iowa, 2015 Every flash flood watch in 2015

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.