Alert archive / South Dakota / Flash Flood Warnings in 2011

Flash Flood Warning 25, NWS Rapid City, SD

July 14, 2011Perkins County, South Dakota

NWS Rapid City, SD issued this flash flood warning at Jul 14, 2011, 8:23 PM MDT for Perkins County, South Dakota. It was in force for 4 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 14, 2011, 8:23 PM MDT (02:23 UTC)
Expired
Jul 15, 2011, 12:37 AM MDT
In force
4 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 02:24 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

Bismarck Municip, ND (KBIS), launched 00:00Z, 2.4 hours before the alert went out and 197 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, Bismarck Municip, ND at 00:00Z on 2011-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2132 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Bismarck Municip, ND at 00:00Z on 2011-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 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
2132 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
698 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.2

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 14, 6:46 PM MDTSevere Thunderstorm WarningUNRPerkins22 min
Jul 14, 7:12 PM MDTSevere Thunderstorm WarningUNRPerkins63 min
Jul 14, 7:54 PM MDTSevere Thunderstorm WarningUNRPerkins, Ziebach81 min
Jul 14, 8:42 PM MDTAreal Flood AdvisoryUNRPerkins, Ziebach4 hr
Jul 15, 3:20 AM MDTExcessive Heat WarningUNRBennett, Haakon, Jackson, Meade, Mellette, Perkins and 3 more5 days

Nearby

Flash Flood Warnings in South Dakota, 2011Every 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.