Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1523

July 20, 20125 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2012, 6:00 PM MDT for 5 counties in South Dakota. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Jul 20, 2012, 6:00 PM MDT (00:00 UTC)
Expired
Jul 20, 2012, 7:30 PM MDT
In force
90 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Custer County, SD, Haakon County, SD, Lawrence County, SD, Meade County, SD, Pennington County, SD

The radar

The Rapid City radar (KUDX), 3 km from the middle of the area, began a volume at 00:00 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 00:00Z, 0.0 hours before the alert went out and 9 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, Rapid City, SD at 00:00Z on 2012-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Rapid City, SD at 00:00Z on 2012-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3532 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
329 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.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 1:54 PM MDTMesoscale DiscussionSPCButte, Custer, Fall River, Lawrence, Meade, Pennington96 min
Jul 21, 4:25 PM MDTMesoscale DiscussionSPCButte, Harding, Lawrence, Meade, Perkins65 min
Jul 21, 4:41 PM MDTSevere Thunderstorm WatchSPCBennett, Butte, Custer, Fall River, Haakon, Harding and 6 more7 hr

Nearby

Mesoscale Discussions in South Dakota, 2012Every mesoscale discussion in 2012

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.