Alert archive / South Dakota / Flash Flood Warnings in 2011

Flash Flood Warning 22, NWS Rapid City, SD

July 6, 2011Perkins County, South Dakota

NWS Rapid City, SD issued this flash flood warning at Jul 6, 2011, 8:37 AM MDT for Perkins County, South Dakota. It was in force for 6 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 6, 2011, 8:37 AM MDT (14:37 UTC)
Expired: Jul 6, 2011, 2:30 PM MDT
In force: 6 hr
Issued by: NWS Rapid City, SD
Area: Storm-based polygon
Flood severity: None

County Perkins County, SD

The radar

The Rapid City radar (KUDX), 154 km from the middle of the area, began a volume at 14:37 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

Rapid City, SD (KUNR), launched 12:00Z, 2.6 hours before the alert went out and 161 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: 1752 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 547 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Rapid City, SD wrote its last area forecast discussion before this flash flood warning went out at Jul 6, 3:13 AM MDT, 5 hours 24 minutes earlier.

Area forecast discussion, Jul 6, 3:13 AM MDT, 5 hours 24 minutes before

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Hazardous weather outlook, Jul 6, 5:35 AM MDT, 3 hours 2 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
535 AM MDT WED JUL 6 2011

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-061135-
BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-
HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK-
NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS-
NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-
SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS-
SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-
WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH-
535 AM MDT (635 AM CDT) WED JUL 6 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND
NORTHEASTERN WYOMING.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE AREA TODAY AND
TONIGHT. THERE IS A SLIGHT RISK OF SEVERE STORMS THAT COULD
PRODUCE LARGE HAIL AND DAMAGING WIND GUSTS. SOME OF THESE STORMS
WILL ALSO HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A CHANCE FOR THUNDERSTORMS EACH DAY FOR THE REST OF THIS
WEEK INTO EARLY NEXT WEEK. THERE IS A SLIGHT RISK OF SEVERE STORMS
EACH DAY THROUGH SATURDAY...WITH LARGE HAIL AND DAMAGING WIND GUSTS
POSSIBLE. THE CURRENT WEATHER PATTERN ALSO FAVORS THE POSSIBILITY FOR
LOCALLY HEAVY RAINFALL AS WELL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.

In the hours before

Special weather statement, Jul 6, 4:47 AM MDT, 3 hours 50 minutes before

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Special weather statement, Jul 6, 5:21 AM MDT, 3 hours 16 minutes before

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Special weather statement, Jul 6, 7:11 AM MDT, 1 hour 26 minutes before

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Special weather statement, Jul 6, 7:54 AM MDT, 43 minutes before

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Special weather statement, Jul 6, 7:56 AM MDT, 41 minutes before

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The office that day

Everything else NWS Rapid City, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 6, 10:57 AM MDT	Areal Flood Advisory	UNR	Custer, Pennington	3 hr
Jul 6, 12:42 PM MDT	Severe Thunderstorm Warning	UNR	Jackson	38 min
Jul 6, 1:21 PM MDT	Flash Flood Warning	UNR	Bennett, Jackson	3 hr
Jul 6, 5:20 PM MDT	Severe Thunderstorm Warning	UNR	Perkins	55 min
Jul 5, 6:19 PM MDT	Severe Thunderstorm Warning	UNR	Weston	56 min
Jul 5, 6:47 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	58 min
Jul 5, 6:50 PM MDT	Severe Thunderstorm Warning	UNR	Campbell, Weston	40 min
Jul 5, 8:03 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	72 min
Jul 5, 8:23 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	82 min

Nearby

Flash Flood Warnings in South Dakota, 2011 Every flash flood warning in 2011

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.