Alert archive / South Dakota / Flash Flood Warnings in 2020

Flash Flood Warning 8, NWS Rapid City, SD

July 29, 2020Oglala Lakota County, South Dakota

NWS Rapid City, SD issued this flash flood warning at Jul 29, 2020, 2:40 PM MDT for Oglala Lakota County, South Dakota. It was in force for 5 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 29, 2020, 2:40 PM MDT (20:40 UTC)
Expired
Jul 29, 2020, 7:55 PM MDT
In force
5 hr
Issued by
NWS Rapid City, SD
Area
Storm-based polygon
Flood severity
None

County Oglala Lakota County, SD

The radar

The Rapid City radar (KUDX), 91 km from the middle of the area, began a volume at 20:40 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 8.7 hours before the alert went out and 293 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, N. Platte/Lee Bi, NE at 12:00Z on 2020-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 741 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, N. Platte/Lee Bi, NE at 12:00Z on 2020-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 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
741 J/kg
Mixed-layer CIN
-57 J/kg
Mixed-layer LCL
1128 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 1:40 PM MDTAreal Flood AdvisoryUNROglala Lakota3 hr
Jul 29, 2:13 PM MDTSpecial Weather StatementUNROglala Lakota47 min
Jul 29, 3:08 PM MDTSpecial Weather StatementUNRJackson52 min
Jul 29, 3:33 PM MDTAreal Flood AdvisoryUNRHaakon, Jackson3 hr
Jul 29, 4:35 PM MDTAreal Flood AdvisoryUNRHaakon, Jackson3 hr
Jul 29, 5:58 PM MDTAreal Flood WarningUNRHaakon, Jackson4 hr

Nearby

Flash Flood Warnings in South Dakota, 2020Every flash flood warning in 2020

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.